Bio

Bio


Kuldev Singh is Professor of Ophthalmology and Director of the Glaucoma Service. He received his MD and MPH degrees from the Johns Hopkins University and was a Dana Foundation Fellow at the Wilmer Eye Institute. Following residency training at the Casey Eye Institute, OHSU and a Heed Foundation Fellowship at the Bascom Palmer Eye Institute, Dr. Singh joined the Stanford faculty in 1992 He has published over 125 original peer-reviewed articles, delivered over 200 invited lectures on six continents, edited two textbooks and served on the editorial boards of ten ophthalmic publications. Dr. Singh’s current research interests include glaucoma and cataract surgical trials, epidemiology, genetics as well as health care delivery in underserved communities in the United States and overseas. His clinical practice focuses on the medical, laser and surgical management of glaucoma and cataract.

Dr. Singh is President of the American Glaucoma Society and serves on the Senior Advisory Committee of the International Society of Glaucoma Surgery. He is immediate past Executive Vice President and serves on the Board of Governors of the World Glaucoma Association. Dr. Singh is a member of the FDA Advisory Committee on Ophthalmic Devices and previously served as a Chair and Methodologist for the Ophthalmic Technology Assessment Panel of the American Academy of Ophthalmology(AAO) Dr. Singh has received the Senior Achievement Award and two Secretariat Awards from AAO. He served as an Academic Advising Dean at the School of Medicine from 2002-2005 and two three year terms as an elected at-large member of the Faculty Senate from 2006-2012. Dr. Singh received the 2006 School of Medicine Franklin G. Ebaugh Jr. Award and was one of two recipients of the 2012 University-wide Asian American Faculty Award. He in one of seven individuals and the second American to have received the WGA Founder's Award, the biennially presented highest honor of the Association recognizing contributions to the profession.

Clinical Focus


  • glaucoma/cataract
  • cataract surgery
  • Ophthalmology
  • glaucoma surgery

Academic Appointments


Administrative Appointments


  • Board of Governors, World Glaucoma Association (2007 - 2017)
  • President, American Glaucoma Society (2013 - 2015)
  • Chair, Board of Directors, Glaucoma Research Foundation (2009 - 2011)
  • Executive Vice President, World Glaucoma Association (2008 - 2012)
  • Academic Advising Dean, Stanford University School of Medicine (2002 - 2005)
  • Residency Training Program Director, Department of Ophthalmology, Stanford University (1993 - 1996)

Honors & Awards


  • Founder's Award, World Glaucoma Association (2013)
  • Asian American Faculty Award, Stanford University (2012)
  • Franklin G. Ebaugh Jr. Award for Advising Medical Students, Stanford University School of Medicine (2006)
  • Senior Achievement Award, American Academy of Ophthalmology (2005)
  • Best Doctor, Best Doctors in America (1996-)
  • Heed Fellowship, The Heed Foundation (1991-92)
  • Eleanor Naylor Dana Charitable Trust Fellowship, Dana Foundation/Johns Hopkins University School of Medicine (1986-87)
  • James McGill Award, McGill University (1979)

Boards, Advisory Committees, Professional Organizations


  • Standing Member, U.S. FDA Advisory Committee on Ophthalmic Devices (2014 - Present)
  • Consultant, U.S. Food and Drug Administration (2011 - Present)
  • Associate Examiner, American Board of Ophthalmology (1998 - Present)
  • Chair, Ethics Task Force, American Glaucoma Society (2011 - 2013)
  • Chair, Ophthalmic Technology Assessment Committee Glaucoma Panel, American Academy of Ophthalmology (2003 - 2009)

Professional Education


  • Fellowship:Johns Hopkins University (1987) MD
  • Board Certification: Ophthalmology, American Board of Ophthalmology (1992)
  • Fellowship:Bascom Palmer Eye Institute (1992) FL
  • Residency:Oregon Health Sciences Univ Hospital (1991) OR
  • Internship:Greater Baltimore Medical Ctr (1988) MD
  • Medical Education:Johns Hopkins University (1986) MD

Community and International Work


  • Adherence and Disease Severity, San Francisco General Hospital

    Partnering Organization(s)

    UCSF

    Location

    Bay Area

    Ongoing Project

    No

    Opportunities for Student Involvement

    Yes

  • Barriers to Glaucoma Care, Madurai, India

    Partnering Organization(s)

    Aravind Eye Hospital

    Location

    International

    Ongoing Project

    No

    Opportunities for Student Involvement

    Yes

  • Antimetabolites and Glaucoma Surgery, Ghana

    Partnering Organization(s)

    Cape Coast Eye Clinic

    Location

    International

    Ongoing Project

    No

    Opportunities for Student Involvement

    No

Research & Scholarship

Current Research and Scholarly Interests


Glaucoma, clinical epidemiology

Teaching

2013-14 Courses


Postdoctoral Advisees


Publications

Journal Articles


  • Association between Visual Field Defects and Quality of Life in the United States. Ophthalmology Qiu, M., Wang, S. Y., Singh, K., Lin, S. C. 2014; 121 (3): 733-740

    Abstract

    To investigate the association between visual field defects and quality of life in the United States population.Cross-sectional study.A total of 5186 participants in the 2005 through 2008 National Health and Nutrition Examination Survey 40 years of age and older without a self-reported history of age-related macular degeneration or prior refractive surgery who had undergone frequency doubling technology perimetric testing.Frequency doubling technology perimetry was performed in both eyes. Results from the better eye were used to categorize subjects as normal or having mild, moderate, or severe visual field loss. Subjects completed surveys about their visual and physical functioning ability.Disability pertaining to 6 vision-related activities, 2 visual function questions, and 5 physical functioning domains.Eighty-one percent of subjects had normal visual fields and 10%, 7%, and 2% demonstrated mild, moderate, and severe visual field defects, respectively. Subjects with greater severity of visual field defects had greater difficulty with vision-related activities. Subjects with severe visual field defects demonstrated the greatest odds of difficulty with all 6 activities. The 2 activities impacted most adversely were daytime driving in familiar places (odds ratio [OR], 12.4; 95% confidence interval [CI], 6.1-25.1) and noticing objects off to the side when walking (OR, 7.7; 95% CI, 4.7-12.7). Subjects with severe visual field defects had greater odds of worrying about eyesight (OR, 3.4; 95% CI, 2.0-5.8) and being limited by vision in the time spent on daily activities (OR, 5.1; 95% CI, 3.0-8.5). Subjects with severe visual field defects demonstrated the greatest odds of difficulty with 3 physical function domains, including activities of daily living (OR, 2.45; 95% CI, 1.37-4.38), instrumental activities of daily living (OR, 2.45; 95% CI, 1.37-4.38), as well as leisure and social activities (OR, 3.29; 95% CI, 1.87-5.77).Greater severity of visual field abnormality was associated with significantly greater odds of disability with vision-related function and physical function. These findings support the necessity of routine screening to find those who may benefit from therapy to prevent progressive glaucomatous vision loss.

    View details for DOI 10.1016/j.ophtha.2013.09.043

    View details for PubMedID 24342021

  • Association of CAV1/CAV2 Genomic Variants with Primary Open-Angle Glaucoma Overall and by Gender and Pattern of Visual Field Loss OPHTHALMOLOGY Loomis, S. J., Kang, J. H., Weinreb, R. N., Yaspan, B. L., Bailey, J. N., Gaasterland, D., Gaasterland, T., Lee, R. K., Lichter, P. R., Budenz, D. L., Liu, Y., Realini, T., Friedman, D. S., McCarty, C. A., Moroi, S. E., Olson, L., Schuman, J. S., Singh, K., Vollrath, D., Wollstein, G., Zack, D. J., Brilliant, M., Sit, A. J., Christen, W. G., Fingert, J., Kraft, P., Zhang, K., Allingham, R. R., Pericak-Vance, M. A., Richards, J. E., Hauser, M. A., Haines, J. L., Pasquale, L. R., Wiggs, J. L. 2014; 121 (2): 508-516

    Abstract

    The CAV1/CAV2 (caveolin 1 and caveolin 2) genomic region previously was associated with primary open-angle glaucoma (POAG), although replication among independent studies has been variable. The aim of this study was to assess the association between CAV1/CAV2 single nucleotide polymorphisms (SNPs) and POAG in a large case-control dataset and to explore associations by gender and pattern of visual field (VF) loss further.Case-control study.We analyzed 2 large POAG data sets: the Glaucoma Genes and Environment (GLAUGEN) study (976 cases, 1140 controls) and the National Eye Institute Glaucoma Human Genetics Collaboration (NEIGHBOR) consortium (2132 cases, 2290 controls).We studied the association between 70 SNPs located within the CAV1/CAV2 genomic region in the GLAUGEN and NEIGHBOR studies, both genotyped on the Illumina Human 660WQuadv1C BeadChip array and imputed with the Markov Chain Haplotyping algorithm using the HapMap 3 reference panel. We used logistic regression models of POAG in the overall population and separated by gender, as well as by POAG subtypes defined by type of VF defect (peripheral or paracentral). Results from GLAUGEN and NEIGHBOR were meta-analyzed, and a Bonferroni-corrected significance level of 7.7 × 10(-4) was used to account for multiple comparisons.Overall POAG, overall POAG by gender, and POAG subtypes defined by pattern of early VF loss.We found significant associations between 10 CAV1/CAV2 SNPs and POAG (top SNP, rs4236601; pooled P = 2.61 × 10(-7)). Of these, 9 were significant only in women (top SNP, rs4236601; pooled P = 1.59 × 10(-5)). Five of the 10 CAV1/CAV2 SNPs were associated with POAG with early paracentral VF (top SNP, rs17588172; pooled P = 1.07 × 10(-4)), and none of the 10 were associated with POAG with peripheral VF loss only or POAG among men.CAV1/CAV2 SNPs were associated significantly with POAG overall, particularly among women. Furthermore, we found an association between CAV1/CAV2 SNPs and POAG with paracentral VF defects. These data support a role for caveolin 1, caveolin 2, or both in POAG and suggest that the caveolins particularly may affect POAG pathogenesis in women and in patients with early paracentral VF defects.

    View details for DOI 10.1016/j.ophtha.2013.09.012

    View details for Web of Science ID 000330579200016

    View details for PubMedID 24572674

  • The impact of cataract surgery on glaucoma care CURRENT OPINION IN OPHTHALMOLOGY Shrivastava, A., Singh, K. 2014; 25 (1): 19-25

    Abstract

    To summarize the effects of cataract surgery on the management of glaucoma, in terms of the effect on both the intraocular pressure (IOP) and postoperative diagnostic as well as therapeutic considerations.Recent evidence corroborates prior data demonstrating significant and sustained IOP reduction after cataract extraction, particularly in closed-angle variants of glaucoma, but also in individuals with open-angle glaucoma or ocular hypertension. Performing cataract surgery after trabeculectomy increases the odds of filtration failure with the likelihood of this adverse effect being inversely proportional to the duration between the glaucoma and cataract procedures. Although cataract has a significant effect on the results of visual field testing, the Visual Field Index may be less influenced than other parameters such as the mean and pattern deviation. The accuracy of time-domain ocular coherence tomography and spectral-domain ocular coherence tomography are also negatively impacted by cataract.Considering cataract surgery as an IOP-lowering procedure may be appropriate in select patients. Performing cataract extraction prior to glaucoma surgery has numerous benefits. The sequence of the procedures performed has implications in terms of complications, surgical success, and diagnostics. Reestablishing perimetric and structural baselines with imaging modalities is appropriate after cataract surgery is performed in glaucoma patients.

    View details for DOI 10.1097/ICU.0000000000000010

    View details for Web of Science ID 000327996600004

    View details for PubMedID 24270598

  • Genomewide association study and meta-analysis of intraocular pressure Human Genetics Ozel, A., Moroi, S., Reed, D., Nika, M., Schmidt, C., Akbari, S., et al 2014; 1 (133): 41-57
  • Things Go Better with Cataract Surgery OPHTHALMOLOGY Singh, K. 2014; 121 (1): 1-1

    View details for DOI 10.1016/j.ophtha.2013.08.001

    View details for Web of Science ID 000329169500008

    View details for PubMedID 24388392

  • Evaluation of the Anterior Chamber Angle in Glaucoma A Report by the American Academy of Ophthalmology OPHTHALMOLOGY Smith, S. D., Singh, K., Lin, S. C., Chen, P. P., Chen, T. C., Francis, B. A., Jampel, H. D. 2013; 120 (10): 1985-1997

    Abstract

    To assess the published literature pertaining to the association between anterior segment imaging and gonioscopy and to determine whether such imaging aids in the diagnosis of primary angle closure (PAC).Literature searches of the PubMed and Cochrane Library databases were last conducted on July 6, 2011. The searches yielded 371 unique citations. Members of the Ophthalmic Technology Assessment Committee Glaucoma Panel reviewed the titles and abstracts of these articles and selected 134 of possible clinical significance for further review. The panel reviewed the full text of these articles and identified 79 studies meeting the inclusion criteria, for which the panel methodologist assigned a level of evidence based on a standardized grading scheme adopted by the American Academy of Ophthalmology. Three, 70, and 6 studies were rated as providing level I, II, and III evidence, respectively.Quantitative and qualitative parameters defined from ultrasound biomicroscopy (UBM), anterior segment optical coherence tomography (OCT), Scheimpflug photography, and the scanning peripheral anterior chamber depth analyzer (SPAC) demonstrate a strong association with the results of gonioscopy. There is substantial variability in the type of information obtained from each imaging method. Imaging of structures posterior to the iris is possible only with UBM. Direct imaging of the anterior chamber angle (ACA) is possible using UBM and OCT. The ability to acquire OCT images in a completely dark environment allows greater sensitivity in detecting eyes with appositional angle closure. Noncontact imaging using OCT, Scheimpflug photography, or SPAC makes these methods more attractive for large-scale PAC screening than contact imaging using UBM.Although there is evidence suggesting that anterior segment imaging provides useful information in the evaluation of PAC, none of these imaging methods provides sufficient information about the ACA anatomy to be considered a substitute for gonioscopy. Longitudinal studies are needed to validate the diagnostic significance of the parameters measured by these instruments for prospectively identifying individuals at risk for PAC.Proprietary or commercial disclosure may be found after the references.

    View details for DOI 10.1016/j.ophtha.2013.05.034

    View details for Web of Science ID 000325086400014

    View details for PubMedID 23978623

  • Patient-Related and System-Related Barriers to Glaucoma Follow-up in a County Hospital Population INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Lee, B. W., Murakami, Y., Duncan, M. T., Kao, A. A., Huang, J., Lin, S., Singh, K. 2013; 54 (10): 6542-6548

    Abstract

    To identify the barriers to glaucoma follow-up and to assess how ethnicity influences the effect of such barriers among patients in a county hospital population.This cross-sectional study included 152 patients, 76 with poor clinic follow-up and 76 with good clinic follow-up, who were recruited at the San Francisco General Hospital glaucoma clinic as part of a case-control study. All subjects were required to be established patients with glaucoma initially seen and diagnosed in the clinic at least 1 year before enrollment. An oral questionnaire pertaining to the barriers to follow-up for glaucoma, as well as patient ethnicity, was administered to all participating subjects. The main outcome measure was the prevalence of significant barriers to follow-up, both overall and stratified by ethnicity.The most prevalent barriers to follow-up included long clinic waiting times (75%), appointment scheduling difficulties (38%), the effect of other medical or physical comorbidities (29%), and difficulties related to medical interpretation (23%). While several barriers were cited as being important across different ethnicities, Latinos and Asian-Pacific Islanders were particularly affected by difficulties related to medical interpretation (P = 0.0001) and long waiting times in the clinic (P = 0.048).Understanding patient-reported barriers to glaucoma follow-up and their variation based on ethnicity may give providers insight as to why patients do not adhere to follow-up recommendations. Strategies to improve follow-up may include reduced clinic wait times, simplified appointment scheduling, and provision of appropriate education and counseling regardless of the patient's native language and ethnicity.

    View details for DOI 10.1167/iovs.13-12108

    View details for Web of Science ID 000326567700011

    View details for PubMedID 23982843

  • Glaucoma Prevalence and the Intake of Iron and Calcium in a Population-based Study CURRENT EYE RESEARCH Wang, S. Y., Singh, K., Lin, S. C. 2013; 38 (10): 1049-1056

    Abstract

    Previous work has suggested a possible relationship between nutritional supplementation with iron and calcium, and a diagnosis of glaucoma. The present study investigates the association between dietary and total calcium and iron consumption with a diagnosis of glaucoma.This cross-sectional study included 6316 participants in the National Health and Nutrition Examination Survey (NHANES 2005-2008), age 40 or older, who participated in the dietary interview portion of NHANES. Intake of the oxidants calcium and iron was assessed using the National Cancer Institute Method of analyzing data from multiple 24-h dietary recall interviews. Participants self-reported the presence or absence of glaucoma as well as information pertaining to demographics, health-related behaviors and comorbidities.Adjusted odds of glaucoma increased with higher total consumption of calcium (p-trend <0.0001) and iron (p-trend <0.0001). Adjusted odds of glaucoma was significantly greater for total calcium intake at the third (OR 1.58, 95% CI 1.32-1.89) and fourth quintile levels (OR 1.21, 95% CI 1.03-1.43) and for total iron intake at the fourth (OR 2.95, 95% CI 2.52-3.45) and fifth quintile levels (OR 1.58, 95% CI 1.36-1.83), compared with the corresponding lowest quintile of intake. In contrast, a tendency towards decreased odds of glaucoma was observed with increasing dietary calcium (p-trend = 0.0008) and iron intake (p-trend = 0.0022).While greater total consumption of calcium and iron may be associated with increased odds of glaucoma, dietary rather than supplemental consumption of these oxidants was found to be associated with lower odds of glaucoma. Additional research is necessary to elucidate the relationship between glaucoma and oxidant intake from foods versus supplements, and to prospectively evaluate whether oxidant intake is related to glaucoma incidence and progression.

    View details for DOI 10.3109/02713683.2013.803124

    View details for Web of Science ID 000323719500006

    View details for PubMedID 23790096

  • The NEIGHBOR Consortium Primary Open-Angle Glaucoma Genome-wide Association Study: Rationale, Study Design, and Clinical Variables JOURNAL OF GLAUCOMA Wiggs, J. L., Hauser, M. A., Abdrabou, W., Allingham, R. R., Budenz, D. L., DelBono, E., Friedman, D. S., Kang, J. H., Gaasterland, D., Gaasterland, T., Lee, R. K., Lichter, P. R., Loomis, S., Liu, Y., McCarty, C., Medeiros, F. A., Moroi, S. E., Olson, L. M., Realini, A., Richards, J. E., Rozsa, F. W., Schuman, J. S., Singh, K., Stein, J. D., Vollrath, D., Weinreb, R. N., Wollstein, G., Yaspan, B. L., Yoneyama, S., Zack, D., Zhang, K., Pericak-Vance, M., Pasquale, L. R., Haines, J. L. 2013; 22 (7): 517-525

    Abstract

    Primary open-angle glaucoma (POAG) is a common disease with complex inheritance. The identification of genes predisposing to POAG is an important step toward the development of novel gene-based methods of diagnosis and treatment. Genome-wide association studies (GWAS) have successfully identified genes contributing to complex traits such as POAG however, such studies frequently require very large sample sizes, and thus, collaborations and consortia have been of critical importance for the GWAS approach. In this report we describe the formation of the NEIGHBOR consortium, the harmonized case control definitions used for a POAG GWAS, the clinical features of the cases and controls, and the rationale for the GWAS study design.

    View details for DOI 10.1097/IJG.0b013e31824d4fd8

    View details for Web of Science ID 000324388300003

    View details for PubMedID 22828004

  • The Association Between Compliance With Recommended Follow-up and Glaucomatous Disease Severity in a County Hospital Population AMERICAN JOURNAL OF OPHTHALMOLOGY Ung, C., Murakami, Y., Zhang, E., Alfaro, T., Zhang, M., Seider, M. I., Singh, K., Lin, S. C. 2013; 156 (2): 362-369

    Abstract

    PURPOSE: To assess the association between insufficient follow-up and clinical parameters such as disease severity and medication use among glaucoma patients at a metropolitan county hospital. DESIGN: Cross-sectional study. METHODS: Two-hundred and six patients with established glaucoma were recruited from San Francisco General Hospital. Subjects were classified based on compliance with recommended follow-up examination intervals over the year preceding commencement of the study, as determined by patient medical records. Glaucoma severity was determined based on the American Academy of Ophthalmology Preferred Practice Patterns guidelines. Multivariate logistic regression analysis was used to assess the relationship between adherence with follow-up visits and disease severity. RESULTS: After adjustment for the impact of potential confounding variables, subjects with severe glaucomatous disease were found to have been less adherent to their recommended follow-up than those patients with mild or moderate glaucomatous disease (adjusted OR 1.89, 95% CI 1.21-2.94; P = .01). Subjects who were on glaucoma medications were found to be less adherent to follow-up recommendations (adjusted OR 3.29, 95% CI 1.41-7.65, P = .01). CONCLUSION: Subjects with poor follow-up adherence were significantly more likely to have severe glaucomatous disease, suggesting that poor follow-up may contribute to disease worsening or, alternatively, those with more severe disease are less inclined to follow up at appropriate intervals.

    View details for DOI 10.1016/j.ajo.2013.03.005

    View details for Web of Science ID 000322748200022

    View details for PubMedID 23601654

  • Estrogen pathway polymorphisms in relation to primary open angle glaucoma: An analysis accounting for gender from the United States MOLECULAR VISION Pasquale, L. R., Loomis, S. J., Weinreb, R. N., Kang, J. H., Yaspan, B. L., Bailey, J. C., Gaasterland, D., Gaasterland, T., Lee, R. K., Scott, W. K., Lichter, P. R., Budenz, D. L., Liu, Y., Realini, T., Friedman, D. S., McCarty, C. A., Moroi, S. E., Olson, L., Schuman, J. S., Singh, K., Vollrath, D., Wollstein, G., Zack, D. J., Brilliant, M., Sit, A. J., Christen, W. G., Fingert, J., Kraft, P., Zhang, K., Allingham, R. R., Pericak-Vance, M. A., Richards, J. E., Hauser, M. A., Haines, J. L., Wiggs, J. L. 2013; 19: 1471-1481

    Abstract

    Circulating estrogen levels are relevant in glaucoma phenotypic traits. We assessed the association between an estrogen metabolism single nucleotide polymorphism (SNP) panel in relation to primary open angle glaucoma (POAG), accounting for gender.We included 3,108 POAG cases and 3,430 controls of both genders from the Glaucoma Genes and Environment (GLAUGEN) study and the National Eye Institute Glaucoma Human Genetics Collaboration (NEIGHBOR) consortium genotyped on the Illumina 660W-Quad platform. We assessed the relation between the SNP panels representative of estrogen metabolism and POAG using pathway- and gene-based approaches with the Pathway Analysis by Randomization Incorporating Structure (PARIS) software. PARIS executes a permutation algorithm to assess statistical significance relative to the pathways and genes of comparable genetic architecture. These analyses were performed using the meta-analyzed results from the GLAUGEN and NEIGHBOR data sets. We evaluated POAG overall as well as two subtypes of POAG defined as intraocular pressure (IOP) ≥22 mmHg (high-pressure glaucoma [HPG]) or IOP <22 mmHg (normal pressure glaucoma [NPG]) at diagnosis. We conducted these analyses for each gender separately and then jointly in men and women.Among women, the estrogen SNP pathway was associated with POAG overall (permuted p=0.006) and HPG (permuted p<0.001) but not NPG (permuted p=0.09). Interestingly, there was no relation between the estrogen SNP pathway and POAG when men were considered alone (permuted p>0.99). Among women, gene-based analyses revealed that the catechol-O-methyltransferase gene showed strong associations with HTG (permuted gene p≤0.001) and NPG (permuted gene p=0.01).The estrogen SNP pathway was associated with POAG among women.

    View details for Web of Science ID 000321786700003

    View details for PubMedID 23869166

  • Glaucoma severity and medication adherence in a county hospital population. Ophthalmology Ung, C., Zhang, E., Alfaro, T., Murakami, Y., Zhang, M., Seider, M. I., Lin, S. C., Singh, K. 2013; 120 (6): 1150-1157

    Abstract

    To assess the association between disease severity and adherence with glaucoma medications in a county hospital population.Cross-sectional study.A total of 126 patients diagnosed with glaucoma receiving intraocular pressure (IOP)-lowering medication were recruited from the San Francisco General Hospital Ophthalmology Clinic.Subjects completed an oral questionnaire to assess demographic information, knowledge of glaucoma, and perceptions of glaucoma medication adherence. Glaucoma disease severity was classified according to the American Academy of Ophthalmology's Preferred Practice Pattern guidelines. Medication adherence was measured for each patient by obtaining pharmacy refill data and calculating medication possession ratio (MPR), that is, the ratio of total days' supply of medication during a 365-day period. Adherence was measured retrospectively over the 18-month period before study entry. Subjects with an MPR >80% were considered adherent.Medication adherence.Subjects with mild or moderate glaucoma were more likely to be nonadherent to their prescribed glaucoma medications than those with severe disease (adjusted odds ratio [OR], 1.54; 95% confidence interval [CI], 1.03-2.31; P = 0.04). Age, gender, race, education level, years of glaucoma, number of medications, and glaucoma diagnosis were not found to be statistically significantly associated with adherence.Patients with severe glaucoma were more likely to adhere to their topical IOP-lowering medication regimen than those with milder glaucomatous disease.Proprietary or commercial disclosure may be found after the references.

    View details for DOI 10.1016/j.ophtha.2012.11.026

    View details for PubMedID 23453512

  • Myopia and glaucoma: diagnostic and therapeutic challenges CURRENT OPINION IN OPHTHALMOLOGY Chang, R. T., Singh, K. 2013; 24 (2): 96-101

    Abstract

    There is strong epidemiologic evidence linking myopia with glaucomatous disease, but a myopic optic nerve can pose significant challenges with regard to making the correct diagnosis of glaucoma. This review provides an overview of these diagnostic and therapeutic challenges with a particular focus on how the growing prevalence of myopia among specific populations may impact such therapy.For a given individual, the link between myopia and glaucoma remains murky in many circumstances, largely because of the fact that it is difficult to separate out myopia-related structural and functional abnormalities from 'true' glaucomatous changes. Using optical coherence tomography (OCT) imaging, myopia has been found to be associated with temporal displacement and thinning of the superior and inferior nerve fiber layer bundles. In particular, sequential generations of 'Asian' ethnicities have been noted to demonstrate increasing rates of high myopia at earlier ages, sometimes with associated visual field defects at normal intraocular pressures. As is the case with any progressive condition, it is often not possible to distinguish glaucomatous from nonglaucomatous disease based on a single examination, and thus follow-up with OCT or perimetry from an established baseline is useful.Although myopia is a known risk factor for glaucoma, it may also result in structural and functional defects that cannot be distinguished from those caused by glaucoma based solely on cross-sectional information. Longitudinal observation may be necessary to distinguish among the multiple effects of myopia on the optic nerve and the natural history of glaucoma, which may vary substantially amongst those who are affected.

    View details for DOI 10.1097/ICU.0b013e32835cef31

    View details for Web of Science ID 000317039900002

    View details for PubMedID 23542349

  • Intravitreal ranibizumab as an adjunct for Ahmed valve surgery in open-angle glaucoma: a pilot study CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY Desai, R. U., Singh, K., Lin, S. C. 2013; 41 (2): 155-158

    Abstract

    To determine the safety and efficacy of intravitreal ranibizumab therapy before and after Ahmed tube insertion for open-angle glaucoma as a means of optimizing postoperative intraocular pressure control.Randomized, controlled trial.Open-angle glaucoma patients scheduled for Ahmed tube insertion, randomized to ranibizumab or control groups.Ranibizumab (0.5 mg in 0.05 mL) was administered intravitreally at three time points: 9 days prior to surgery, 1 month post-surgery and 2 months post-surgery. Control patients underwent the same procedure without ranibizumab.Success at 6 months postoperatively was defined as intraocular pressure <18 mmHg with no adjunctive medications or intraocular pressure <15 mmHg with one adjunctive medication.The study and control arms included six and five subjects, respectively, with four in each arm undergoing combined cataract surgery. In the ranibizumab arm, the preoperative and postoperative intraocular pressure/medication usage was 21.0 ± 6.7 mmHg on 3.2 ± 1.5 medications and 14.7 ± 1.9 mmHg on 0.5 ± 0.8 medications, respectively. In the control arm, preoperative and postoperative intraocular pressure/medication usage was 18.8 ± 3.8 mmHg on 2.8 ± 1.3 medications and 16.2 ± 3.6 mmHg with 1.8 ± 1.6 medications, respectively. Success was achieved in 83% of subjects in the ranibizumab group compared with 40% in the control group (two-tailed Fisher's exact test, P = 0.24).The findings from this small pilot comparative study suggest that intravitreal ranibizumab use may be a safe and potentially effective adjunctive treatment modality in improving success after Ahmed tube placement.

    View details for DOI 10.1111/j.1442-9071.2012.02836.x

    View details for Web of Science ID 000316808300008

    View details for PubMedID 22712537

  • CDKN2B-AS1 Genotype-Glaucoma Feature Correlations in Primary Open-Angle Glaucoma Patients From the United States AMERICAN JOURNAL OF OPHTHALMOLOGY Pasquale, L. R., Loomis, S. J., Kang, J. H., Yaspan, B. L., Abdrabou, W., Budenz, D. L., Chen, T. C., DelBono, E., Friedman, D. S., Gaasterland, D., Gaasterland, T., Grosskreutz, C. L., Lee, R. K., Lichter, P. R., Liu, Y., McCarty, C. A., Moroi, S. E., Olson, L. M., Realini, T., Rhee, D. J., Schuman, J. S., Singh, K., Vollrath, D., Wollstein, G., Zack, D. J., Allingham, R. R., Pericak-Vance, M. A., Weinreb, R. N., Zhang, K., Hauser, M. A., Richards, J. E., Haines, J. L., Wiggs, J. L. 2013; 155 (2): 342-353

    Abstract

    To assess the association between single nucleotide polymorphisms (SNPs) of the gene region containing cyclin-dependent kinase inhibitor 2B antisense noncoding RNA (CDKN2B-AS1) and glaucoma features among primary open-angle glaucoma (POAG) patients.Retrospective observational case series.We studied associations between 10 CDKN2B-AS1 SNPs and glaucoma features among 976 POAG cases from the Glaucoma Genes and Environment (GLAUGEN) study and 1971 cases from the National Eye Institute Glaucoma Human Genetics Collaboration (NEIGHBOR) consortium. For each patient, we chose the feature from the eye with the higher value. We created cohort-specific multivariable models for glaucoma features and then meta-analyzed the results.For 9 of the 10 protective CDKN2B-AS1 SNPs with minor alleles associated with reduced disease risk (eg, the G allele at rs2157719), POAG patients carrying these minor alleles had smaller cup-to-disc ratio (0.05 units smaller per G allele at diagnosis; 95% CI: -0.08, -0.03; P = 6.23E-05) despite having higher intraocular pressure (IOP) (0.70 mm Hg higher per G allele at DNA collection; 95% CI: 0.40, 1.00; P = 5.45E-06). For the 1 adverse rs3217992 SNP with minor allele A associated with increased disease risk, POAG patients with A alleles had larger cup-to-disc ratio (0.05 units larger per A allele at diagnosis; 95% CI: 0.02, 0.07; P = 4.74E-04) despite having lower IOP (-0.57 mm Hg per A allele at DNA collection; 95% CI: -0.84, -0.29; P = 6.55E-05).Alleles of CDKN2B-AS1 SNPs, which influence risk of developing POAG, also modulate optic nerve degeneration among POAG patients, underscoring the role of CDKN2B-AS1 in POAG.

    View details for DOI 10.1016/j.ajo.2012.07.023

    View details for Web of Science ID 000314137400019

    View details for PubMedID 23111177

  • Late Acute Myopia Syndrome Induced by Combination of Sulfonamide Drugs. Journal of glaucoma Kozner, P., Simonova, K., Brozek, B., Singh, K. 2013

    Abstract

    We present a case of late acute myopia syndrome following discontinuation of treatment with a combination of sulphonamide drugs. To the best of our knowledge, this is the first reported case with such a presentation, and suggests that the pathophysiological basis for the acute myopia syndrome is a rapid decrease in serum carbonic anhydrase inhibitors levels which may lead to a rebound increase in the production of aqueous humor and accumulation of suprachoroidal fluid. It is further postulated that there may be a cumulative effect of sulphonamide drug use on carbonic anhydrase activity in the ciliary body epithelium of susceptible individuals.

    View details for PubMedID 23661047

  • Clinical Impact of 8 Prospective, Randomized, Multicenter Glaucoma Trials. Journal of glaucoma Panarelli, J. F., Banitt, M. R., Sidoti, P. A., Budenz, D. L., Singh, K. 2013

    Abstract

    PURPOSE:: To determine the impact of 8 multicenter randomized clinical trials (RCTs) on glaucoma practice. METHODS:: An electronic survey was distributed to the members of the American Glaucoma Society (AGS). Each participant was asked 2 study-specific questions and 1 standard question common to all 8 RCTs assessing the study's impact on clinical practice. RCTs included in the survey were the Advanced Glaucoma Intervention Study (AGIS), Collaborative Initial Glaucoma Treatment Study (CIGTS), Collaborative Normal Tension Glaucoma (CNTG) Study, European Glaucoma Prevention Study (EGPS), Early Manifest Glaucoma Trial (EMGT), Glaucoma Laser Trial (GLT), Ocular Hypertension Treatment Study (OHTS), and Tube Versus Trabeculectomy (TVT) Study. A 5-point Likert scale was used for rating all responses. The practice setting and duration of glaucoma practice was determined for all AGS members who responded. RESULTS:: A total of 206 (23.0%) of 894 AGS members participated in the survey. Among those who responded, 46.4% were self classified as academic practitioners and 53.6% worked in a private practice setting. Mean Likert scores for the standard question evaluating the overall impact of the RCT were OHTS 4.47, CNTG Study 4.13, AGIS 3.78, TVT Study 3.53, EMGT 3.48, CIGTS 3.44, GLT 3.39, and 2.69 EGPS. CONCLUSIONS:: Substantial differences were observed in the clinical impact of several RCTs in glaucoma. The reported impact of each study likely reflects several factors including study timing, design, conduct, and interpretation of results.

    View details for PubMedID 23632410

  • Glaucoma Screening Using Relative Afferent Pupillary Defect. Journal of glaucoma Charalel, R. A., Lin, H. S., Singh, K. 2013

    Abstract

    PURPOSE:: To assess the relative afferent pupillary defect (RAPD) by swinging flashlight as a potentially useful screening test for glaucomatous optic neuropathy. METHODS:: One hundred seven subjects prospectively recruited from a mixed population of glaucomatous and nonglaucomatous patients were examined for a RAPD by 1 individual masked with regard to disease presence. All subjects underwent a swinging flashlight test with, when necessary, the aid of neutral density filters, to determine whether or not a RAPD was present. A determination of glaucoma diagnosis, as well as classification of disease stage, was subsequently assessed based upon review of history and ophthalmic examination. This clinical information regarding glaucomatous disease was ascertained without knowledge of study RAPD status. The acquisition of such clinical information and performance of swinging flashlight testing for RAPD was conducted by different individuals with the latter being a nonophthalmologist. RESULTS:: Statistical analysis demonstrated an odds ratio of 9.71 (95% CI, 3.72-25.40) for glaucomatous disease if a RAPD was present, with a sensitivity of 66.7% and a specificity of 82.9%. Subanalysis of patients who had not previously undergone cataract surgery revealed an odds ratio of 17.05 (95% CI, 4.73-61.44) for glaucomatous disease if a RAPD was present, with a sensitivity of 68.8% and a specificity of 88.6%. CONCLUSIONS:: RAPD screening by a swinging flashlight test with neutral density filters was moderately sensitive and strongly specific for glaucoma. Sensitivity, specificity, and predictive value improved when patients who had previously undergone cataract surgery were removed from the analysis.

    View details for PubMedID 23296370

  • Association between Myopia and Glaucoma in the United States Population INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Qiu, M., Wang, S. Y., Singh, K., Lin, S. C. 2013; 54 (1): 830-835

    Abstract

    To investigate the association between myopia and the prevalence of glaucoma.This cross-sectional study included 5277 participants from the 2005 to 2008 National Health and Nutrition Examination Survey, greater than or equal to 40 years old, without history of cataract or refractive surgery, who underwent auto-refraction measurement. The predictor was refractive status; emmetropia (-0.99 to +0.99 diopters [D]), mild myopia (-1.00 to -2.99 D), moderate myopia (-3.00 to -5.99 D), severe myopia (> -6.00 D), and hyperopia (> 1.00 D). The outcomes were self-reported glaucoma, vertical cup-to-disc ratio and visual field defects as found on frequency doubling technology (FDT) testingOdds of self-reported glaucoma were not significantly increased in mild (odds ratio [OR] 0.90, confidence interval [CI] 0.56-1.45), moderate (OR 1.40, CI 0.62-3.16), or severe (OR 0.26, CI 0.08-0.80) myopes compared with emmetropes. Odds of vertical cup-to-disc ratio greater than or equal to 0.7 were not significantly increased in mild (OR 0.84, CI 0.31-2.25), moderate (OR 0.37, CI 0.04-3.57), or severe (OR 0.85, CI 0.09-8.42) myopes compared with emmetropes. Odds of any visual field defects were significantly increased in mild (OR 2.02, CI 1.28-3.19), moderate (OR 3.09, CI 1.42-6.72), and severe (OR 14.43, CI 5.13-40.61) myopes compared with emmetropes. The ?(2) test indicated a significant difference (P = 0.001) in the distribution of subjects with each category of visual field status across subjects with each refractive status; the proportion of subjects with worse visual field defects increased with worsening myopia severity.The association between myopia and visual field defects may represent an increased risk of glaucoma among myopes, and the lack of association with self-reported glaucoma may suggest a need for greater glaucoma surveillance in this population.

    View details for DOI 10.1167/iovs.12-11158

    View details for Web of Science ID 000314338400109

    View details for PubMedID 23299483

  • Timely cataract surgery for improved glaucoma management JOURNAL OF CATARACT AND REFRACTIVE SURGERY Chang, R. T., Shingleton, B. J., Singh, K. 2012; 38 (10): 1709-1710

    View details for DOI 10.1016/j.jcrs.2012.08.030

    View details for Web of Science ID 000309736500002

    View details for PubMedID 22999597

  • PREVALENCE OF DIABETES MELLITUS AND DIABETIC RETINOPATHY IN FILIPINO VS CAUCASIAN AMERICANS: A RETROSPECTIVE CROSS-SECTIONAL EPIDEMIOLOGIC STUDY OF TWO CONVENIENCE SAMPLES ETHNICITY & DISEASE Sales, C. S., Lee, R. Y., Agadzi, A. K., Hee, M. R., Singh, K., Lin, S. C. 2012; 22 (4): 459-465

    Abstract

    To compare the prevalence of diabetic retinopathy in Filipino and Caucasian Americans in two clinic populations.Retrospective cross-sectional epidemiologic study of two convenience samples.Five hundred twelve Filipino and 600 Caucasian patients aged 40 years or older examined by two community-based comprehensive ophthalmology clinics during a one-year period.The prevalence of self-reported type 2 diabetes mellitus among Filipino (F) and Caucasian Americans (C) was 40.6% and 24.8%, respectively (P<.001). In the subpopulation with type 2 diabetes mellitus (n=375: 208 Filipino; 149 Caucasian), there was a statistically insignificant higher prevalence of diabetic retinopathy among Filipino diabetics compared to Caucasians (F vs C: all forms of diabetic retinopathy, 24.5% vs 16.8%, P=.08; non-proliferative retinopathy, 17.3% vs 12.8%, P=.24; proliferative retinopathy, 7.2% vs. 4.0%, P=.21). In multivariate analyses of the diabetic subpopulation, Filipino ethnicity was not a significant predictor of diabetic retinopathy.Filipino Americans may have a higher prevalence of type 2 diabetes mellitus and diabetic retinopathy than Caucasian Americans. Among those with type 2 diabetes, however, Filipino Americans were not found to be more likely to show manifestations of diabetic retinopathy than Caucasian Americans.

    View details for Web of Science ID 000310559400011

    View details for PubMedID 23140077

  • RAND-like Appropriateness Methodology Consensus for Primary Open-Angle Glaucoma in Latin America AMERICAN JOURNAL OF OPHTHALMOLOGY Fabian Lerner, S., Singh, K., Susanna, R., Wilson, M. R., Lee, B. L., Maul, E. 2012; 154 (3): 460-465

    Abstract

    To report the results of a Latin American consensus panel regarding the diagnosis and management of primary open-angle glaucoma and to compare these results with those from a similar panel in the United States.A RAND-like (Research and Development) appropriateness methodology was used to assess glaucoma practice in Latin America.The 148 polling statements created for the RAND- like analysis in the United States and 10 additional statements specific to glaucoma care in Latin America were presented to a panel of Latin American glaucoma experts. Panelists were polled in private using the RAND- like methodology before and after the panel meeting.Consensus agreement or disagreement among Latin American experts was reached for 51.3% of statements before the meeting and increased to 66.5% in the private, anonymous meeting after polling (79.0% agreement, 21.0% disagreement). Although there was a high degree of concordance (111 of 148 statements; 75%) between the results of this Latin American panel and the United States panel, there were some notable exceptions relating to diagnostic and therapeutic decision making.This RAND-like consensus methodology provides a perspective of how Latin American glaucoma practitioners view many aspects of glaucoma and compares these results with those obtained using a similar methodology from practitioners in the United States. These findings may be helpful to ophthalmologists providing glaucoma care in Latin America and in other regions of the world.

    View details for DOI 10.1016/j.ajo.2012.03.015

    View details for Web of Science ID 000308115600008

    View details for PubMedID 22626620

  • Prevalence and Predictors of Depression Among Participants With Glaucoma in a Nationally Representative Population Sample AMERICAN JOURNAL OF OPHTHALMOLOGY Wang, S. Y., Singh, K., Lin, S. C. 2012; 154 (3): 436-444

    Abstract

    To investigate the prevalence of and risk factors for depression among participants with glaucoma and the predictive value of glaucoma for depression.Cross-sectional study.This study included 6760 participants in the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2008, aged ?40 years, who reported a presence or absence of glaucoma. Demographic and disease-related information was obtained by interview. Self-reported measures of vision were ascertained via items from the Visual Function Questionnaire (VFQ-25). Participants underwent visual acuity examination, fundus photography, and visual field testing with screening frequency-doubling technology (FDT N-30-5). The main outcome was presence of depression, as determined by a score ?10 on the Patient Health Questionnaire-9 (PHQ-9).Prevalence of depression among participants with and without glaucoma was 10.9% (SEM 2.2%) and 6.9% (SEM 0.62%), respectively. While the presence of glaucoma was significantly associated with depression after adjustment for demographic factors (OR 1.80, 95% CI 1.16-2.79), this association was not significant after adjustment for self-reported general health condition (OR 1.35, 95% CI 0.822-2.23). Among participants with glaucoma, objective measures of glaucoma severity were not significant predictors for depression. However, several self-reported measures of visual function were significantly associated with depression.Glaucoma is a significant predictor of depression after adjustment for demographic factors and multiple comorbidities, but not after adjustment for self-reported general health condition. Among participants with glaucoma, self-reported measures of vision were significant risk factors for depression, whereas objective measures of vision were not.

    View details for DOI 10.1016/j.ajo.2012.03.039

    View details for Web of Science ID 000308115600005

    View details for PubMedID 22789562

  • Glaucoma surgery with and without cataract surgery: Revolution or evolution? JOURNAL OF CATARACT AND REFRACTIVE SURGERY Choi, D., Suramethakul, P., Lindstrom, R. L., Singh, K. 2012; 38 (7): 1121-1122

    View details for DOI 10.1016/j.jcrs.2012.05.005

    View details for Web of Science ID 000306164200002

    View details for PubMedID 22727279

  • Genome-Wide Analysis of Central Corneal Thickness in Primary Open-Angle Glaucoma Cases in the NEIGHBOR and GLAUGEN Consortia INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Ulmer, M., Li, J., Yaspan, B. L., Ozel, A. B., Richards, J. E., Moroi, S. E., Hawthorne, F., Budenz, D. L., Friedman, D. S., Gaasterland, D., Haines, J., Kang, J. H., Lee, R., Lichter, P., Liu, Y., Pasquale, L. R., Pericak-Vance, M., Realini, A., Schuman, J. S., Singh, K., Vollrath, D., Weinreb, R., Wollstein, G., Zack, D. J., Zhang, K., Young, T., Allingham, R. R., Wiggs, J. L., Ashley-Koch, A., Hauser, M. A. 2012; 53 (8): 4468-4474

    Abstract

    To investigate the effects of central corneal thickness (CCT)-associated variants on primary open-angle glaucoma (POAG) risk using single nucleotide polymorphisms (SNP) data from the Glaucoma Genes and Environment (GLAUGEN) and National Eye Institute (NEI) Glaucoma Human Genetics Collaboration (NEIGHBOR) consortia.A replication analysis of previously reported CCT SNPs was performed in a CCT dataset (n = 1117) and these SNPs were then tested for association with POAG using a larger POAG dataset (n = 6470). Then a CCT genome-wide association study (GWAS) was performed. Top SNPs from this analysis were selected and tested for association with POAG. cDNA libraries from fetal and adult brain and ocular tissue samples were generated and used for candidate gene expression analysis.Association with one of 20 previously published CCT SNPs was replicated: rs12447690, near the ZNF469 gene (P = 0.001; ? = -5.08 ?m/allele). None of these SNPs were significantly associated with POAG. In the CCT GWAS, no SNPs reached genome-wide significance. After testing 50 candidate SNPs for association with POAG, one SNP was identified, rs7481514 within the neurotrimin (NTM) gene, that was significantly associated with POAG in a low-tension subset (P = 0.00099; Odds Ratio [OR] = 1.28). Additionally, SNPs in the CNTNAP4 gene showed suggestive association with POAG (top SNP = rs1428758; P = 0.018; OR = 0.84). NTM and CNTNAP4 were shown to be expressed in ocular tissues.The results suggest previously reported CCT loci are not significantly associated with POAG susceptibility. By performing a quantitative analysis of CCT and a subsequent analysis of POAG, SNPs in two cell adhesion molecules, NTM and CNTNAP4, were identified and may increase POAG susceptibility in a subset of cases.

    View details for DOI 10.1167/iovs.12-9784

    View details for Web of Science ID 000307096400018

    View details for PubMedID 22661486

  • Dark-light Change of Iris Parameters and Related Factors Among American Caucasians, American Chinese, and Mainland Chinese CURRENT EYE RESEARCH Wang, D., He, M., Wu, L., Kao, A., Pekmezci, M., Singh, K., Lin, S. 2012; 37 (7): 599-605

    Abstract

    To assess the distribution of dark-light changes in iris features and associated factors amongst American Caucasians, American Chinese and mainland Chinese aged 40 years and over.Four gender- and age-matched cohorts: Caucasians, American Chinese, Southern Chinese and Northern Chinese comprised the study population. Anterior segment optical coherence tomography (ASOCT) images were acquired under dark and light conditions. Customized software was used to calculate iris thickness at 750 μm from the scleral spur (IT750), iris curvature (ICurv), iris area (IArea), and pupil diameter (PD) from ASOCT images.Data from 121, 124, 121 and 120 subjects were available for American Caucasian, American Chinese, Southern and Northern Chinese subjects respectively. Caucasians had significantly less dark-light change (Δ) of IT750 and greater ΔPD than Chinese. When using multiple linear regression analyses, the inter-ethnic difference for ΔIT750 was independent of age, gender, refractive error, anterior chamber width and axial length. After controlling for ΔPD, ΔICurv was found to be inversely associated with age (β = -0.001, P = 0.001). Independent predictors of greater ΔPD included younger age (β = -0.02, P = 0.001), Caucasian ethnicity (β = -0.022, P = 0.009) and wider anterior chamber (β = 0.18, P = 0.03).Compared with Caucasians, Chinese irides show greater thickening with light to dark adaptation despite the lesser change of PD in Chinese. The change of iris area per unit change of pupil diameter from dark to light did not differ between ethnicities. These dynamic characteristics intrinsic to Chinese irides may partially account for the substantially increased risk for angle closure among this ethnic group.

    View details for DOI 10.3109/02713683.2012.660593

    View details for Web of Science ID 000305010400007

    View details for PubMedID 22578180

  • Clinical Characterization of Young Chinese Myopes With Optic Nerve and Visual Field Changes Resembling Glaucoma JOURNAL OF GLAUCOMA Kumar, R. S., Baskaran, M., Singh, K., Aung, T. 2012; 21 (5): 281-286

    Abstract

    To clinically characterize young Chinese myopic patients with optic disc changes suggestive of glaucoma.In this prospective study, patients ?50 years of age who had myopia and suspected glaucomatous optic neuropathy (group A) were compared with established glaucoma patients (group B) and normals (group C). Risk factors such as family history of glaucoma and history of vasospasm and ischemic risk factors were compared. Ophthalmic examination included optic disc assessment and static automated perimetry. Peak diurnal intraocular pressure (IOP) and fluctuation were measured for groups A and C.Ninety-two patients were enrolled (32 patients in group A, 43 in group B, and 21 in group C). Mean refractive error differed between group A [-6.59 Diopter sphere (DS); 95% CI, -8.51 to -4.68] and group B (-0.92 DS; 95% CI, -2.05 to 0.19) (P<0.0001) and C (-0.17 DS; 95% CI, -0.48 to 0.14) (P<0.0001). Optic disc tilt was more common in group A (31.3%) compared with group B (16.3%, P=0.01); both groups had comparable vertical cup-to-disc ratios (P=0.58). The visual field mean pattern standard deviation was higher for group A compared with group B (P=0.03), whereas mean deviation was similar (P=0.42); group A had less frequent hemifield defects (P=0.02). Mean peak diurnal IOP in group A (19.0 mm Hg; 95% CI, 17.3-20.7) was significantly higher than group C (15.8 mm Hg; 95% CI, 14.6-17.0, P=0.007); mean IOP fluctuation showed no difference (P=0.19). Ischemic risk factors were more common in group B compared with A (P<0.0001).Although the clinical features of myopia and glaucoma-like optic nerve changes in young Chinese individuals may allow differentiation from older glaucoma patients of the same ethnicity, such a distinction is not reliable enough to make definitive differential management recommendations for these groups in all circumstances at the present time. A prospective observational study with matching of groups on potentially confounding variables is necessary to better assess and compare the natural history of glaucomatous disease in such groups of patients.

    View details for DOI 10.1097/IJG.0b013e318218253b

    View details for Web of Science ID 000305084100001

    View details for PubMedID 21623224

  • Postoperative Complications in the Tube Versus Trabeculectomy (TVT) Study During Five Years of Follow-up AMERICAN JOURNAL OF OPHTHALMOLOGY Gedde, S. J., Herndon, L. W., Brandt, J. D., Budenz, D. L., Feuer, W. J., Schiffman, J. C. 2012; 153 (5): 804-814

    Abstract

    To describe postoperative complications encountered in the Tube Versus Trabeculectomy (TVT) Study during 5 years of follow-up.Multicenter randomized clinical trial.Settings: Seventeen clinical centers. Study Population: Patients 18 to 85 years of age who had previous trabeculectomy and/or cataract extraction with intraocular lens implantation and uncontrolled glaucoma with intraocular pressure (IOP) ?18 mm Hg and ?40 mm Hg on maximum tolerated medical therapy. Interventions: Tube shunt (350-mm(2) Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC 0.4 mg/mL for 4 minutes). Main Outcome Measures: Surgical complications, reoperations for complications, visual acuity, and cataract progression.Early postoperative complications occurred in 22 patients (21%) in the tube group and 39 patients (37%) in the trabeculectomy group (P = .012). Late postoperative complications developed in 36 patients (34%) in the tube group and 38 patients (36%) in the trabeculectomy group during 5 years of follow-up (P = .81). The rate of reoperation for complications was 22% in the tube group and 18% in the trabeculectomy group (P = .29). Cataract extraction was performed in 13 phakic eyes (54%) in the tube group and 9 phakic eyes (43%) in the trabeculectomy group (P = .43).A large number of surgical complications were observed in the TVT Study, but most were transient and self-limited. The incidence of early postoperative complications was higher following trabeculectomy with MMC than tube shunt surgery. The rates of late postoperative complications, reoperation for complications, and cataract extraction were similar with both surgical procedures after 5 years of follow-up.

    View details for DOI 10.1016/j.ajo.2011.10.024

    View details for Web of Science ID 000303964800003

    View details for PubMedID 22244522

  • Treatment Outcomes in the Tube Versus Trabeculectomy (TVT) Study After Five Years of Follow-up AMERICAN JOURNAL OF OPHTHALMOLOGY Gedde, S. J., Schiffman, J. C., Feuer, W. J., Herndon, L. W., Brandt, J. D., Budenz, D. L. 2012; 153 (5): 789-803

    Abstract

    To report 5-year treatment outcomes in the Tube Versus Trabeculectomy (TVT) Study.Multicenter randomized clinical trial.Settings: Seventeen clinical centers. Study population: Patients 18 to 85 years of age who had previous trabeculectomy and/or cataract extraction with intraocular lens implantation and uncontrolled glaucoma with intraocular pressure (IOP) ?18 mm Hg and ?40 mm Hg on maximum tolerated medical therapy. Interventions: Tube shunt (350-mm(2) Baerveldt glaucoma implant) or trabeculectomy with mitomycin C ([MMC]; 0.4 mg/mL for 4 minutes). Main outcome measures: IOP, visual acuity, use of supplemental medical therapy, and failure (IOP >21 mm Hg or not reduced by 20%, IOP ?5 mm Hg, reoperation for glaucoma, or loss of light perception vision).A total of 212 eyes of 212 patients were enrolled, including 107 in the tube group and 105 in the trabeculectomy group. At 5 years, IOP (mean ± SD) was 14.4 ± 6.9 mm Hg in the tube group and 12.6 ± 5.9 mm Hg in the trabeculectomy group (P = .12). The number of glaucoma medications (mean ± SD) was 1.4 ± 1.3 in the tube group and 1.2 ± 1.5 in the trabeculectomy group (P = .23). The cumulative probability of failure during 5 years of follow-up was 29.8% in the tube group and 46.9% in the trabeculectomy group (P = .002; hazard ratio = 2.15; 95% confidence interval = 1.30 to 3.56). The rate of reoperation for glaucoma was 9% in the tube group and 29% in the trabeculectomy group (P = .025).Tube shunt surgery had a higher success rate compared to trabeculectomy with MMC during 5 years of follow-up in the TVT Study. Both procedures were associated with similar IOP reduction and use of supplemental medical therapy at 5 years. Additional glaucoma surgery was needed more frequently after trabeculectomy with MMC than tube shunt placement.

    View details for DOI 10.1016/j.ajo.2011.10.026

    View details for Web of Science ID 000303964800002

    View details for PubMedID 22245458

  • Long-term effect of phacoemulsification on intraocular pressure using phakic fellow eye as control JOURNAL OF CATARACT AND REFRACTIVE SURGERY Chang, T. C., Budenz, D. L., Liu, A., Kim, W. I., Dang, T., Li, C., Iwach, A. G., Radhakrishnan, S., Singh, K. 2012; 38 (5): 866-870

    Abstract

    To investigate the long-term effect of phacoemulsification on intraocular pressure (IOP) in patients with ocular hypertension and open-angle glaucoma.Three multispecialty ophthalmology practices and one glaucoma specialty group.Retrospective comparative case series.Review of medical records of patients with open-angle glaucoma or ocular hypertension who had had unilateral phacoemulsification (without other prior or concurrent ophthalmic procedure) with the fellow eye remaining phakic at least 3 years postoperatively.Preoperatively, the IOP in the surgical and fellow eyes in the 29 patients was 15.66 mm Hg ± 3.33 (SD) and 15.64 ± 4.23 mm Hg (P=.98), respectively. Postoperatively, it was 13.56 ± 2.04 mm Hg and 14.92 ± 2.85 mm Hg, respectively, at 4.5 months (P=.06); 14.88 ± 3.20 mm Hg and 15.27 ± 3.19 mm Hg, respectively, at 1 year (P=.67); 14.16 ± 2.61 mm Hg and 14.95 ± 2.79 mm Hg, respectively, at 2 years (P=.37); and 14.68 ± 3.44 mm Hg and 14.68 ± 2.68 mm Hg at 3 years (P=1.00), respectively. There was no significant difference in the mean number of IOP-lowering medications used in the surgical eyes (1.96 ± 1.40) and fellow eyes (2.08 ± 1.44) postoperatively (P=.77).In a cohort of ocular hypertensive and glaucoma patients, uncomplicated phacoemulsification had no significant IOP-lowering effect compared with the phakic fellow eye for up to 3 years postoperatively. There was also no difference between the mean number of postoperative IOP-lowering medications used in the surgical and fellow eyes.No author has a financial or proprietary interest in any material or method mentioned.

    View details for DOI 10.1016/j.jcrs.2012.01.016

    View details for Web of Science ID 000303846300020

    View details for PubMedID 22370470

  • The Tube Versus Trabeculectomy Study: interpretation of results and application to clinical practice CURRENT OPINION IN OPHTHALMOLOGY Gedde, S. J., Singh, K., Schiffman, J. C., Feuer, W. J. 2012; 23 (2): 118-126

    Abstract

    The Tube Versus Trabeculectomy (TVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube-shunt surgery to trabeculectomy with mitomycin C (MMC) in eyes with previous cataract and/or failed glaucoma surgery. This article interprets results from the TVT Study and applies them to clinical practice.Both tube-shunt surgery and trabeculectomy with MMC produced intraocular pressure (IOP) reduction to the low teens throughout the 5-year duration of the study. Tube-shunt surgery was associated with use of more glaucoma medications than trabeculectomy with MMC during the first 2 years of the study, but medical therapy equalized with longer follow-up. Trabeculectomy with MMC had higher rates of surgical failure and reoperation for glaucoma compared with tube-shunt surgery. Vision loss occurred at a similar rate with the two surgical procedures. Early complications were more frequent after trabeculectomy with MMC relative to tube-shunt surgery, but both procedures had similar rates of late postoperative complications and serious complications.Tube-shunt surgery and trabeculectomy with MMC are both viable surgical options for managing glaucoma in patients who have undergone prior cataract and/or failed filtering surgery. Results of the TVT Study support the expanding use of tube shunts beyond refractory glaucomas.

    View details for DOI 10.1097/ICU.0b013e32834ff2d1

    View details for Web of Science ID 000300455400006

    View details for PubMedID 22249235

  • Differences in iris structural measurements among American Caucasians, American Chinese and mainland Chinese CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY Wang, D., He, M., Wu, L., Yaplee, S., Singh, K., Lin, S. 2012; 40 (2): 162-169

    Abstract

    To assess the distribution of iris structural measurements among American Caucasians, American Chinese and mainland Chinese aged 40years and over, in order to determine associated factors of increased risk for angle closure in Chinese.Prospective multicentre cross-sectional study.Four gender- and age-matched cohorts: Caucasians, American Chinese, Southern Chinese from Guangzhou and Northern Chinese from Beijing were enrolled in this study.Anterior segment optical coherence tomography was utilized to image the anterior chamber. Customized software was used to calculate the related parameters from anterior segment optical coherence tomography images.Iris thickness at 750µm from the scleral spur, iris curvature, iris area, pupil diameter.Data from 121, 124, 121 and 120 subjects were available for American Caucasian, American Chinese, Southern and Northern Mainland Chinese subjects, respectively. The Chinese cohorts did not differ with regard to any of the parameters. Multiple linear regressions indicated that Caucasians had thinner iris thickness at 750µm from the scleral spur and smaller iris area than Chinese after controlling for potential confounders. Female Caucasians had thinner irides (P=0.015) and smaller iris area (P=0.001) than male Caucasians. Female Chinese tended to have more convex irides (P=0.021) than male Chinese. Pupil size was inversely associated with age (P<0.001) in both ethnicities.In dark conditions, Chinese have thicker irides and greater iris area than Caucasians independent of pupil size. Among Chinese, more convex irides in women may account for the higher rate of narrow angles identified in this segment of the Chinese population.

    View details for DOI 10.1111/j.1442-9071.2011.02658.x

    View details for Web of Science ID 000301533200009

    View details for PubMedID 21794048

  • The Association between Glaucoma Prevalence and Supplementation with the Oxidants Calcium and Iron INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Wang, S. Y., Singh, K., Lin, S. C. 2012; 53 (2): 725-731

    Abstract

    To investigate the relationship between supplementary consumption of the oxidants calcium and iron and the prevalence of glaucoma.This cross-sectional study included 3833 participants in the National Health and Nutrition Examination Survey (NHANES) for 2007 and 2008, ? 40 years of age, who reported a presence or absence of glaucoma. Participants were interviewed regarding the use of dietary supplements and antacids during the preceding 30-day period. Data pertaining to the supplementary intake of calcium and iron was aggregated and divided into quintiles. Information regarding the presence or absence of glaucoma and demographics, comorbidities, and health-related behavior was obtained via interview.Participants who consumed ? 800 mg/d of supplementary calcium or ? 18 mg/d of supplementary iron had significantly higher odds of having been diagnosed with glaucoma than did those who had not consumed supplementary calcium or iron, after adjustment for potential confounders (odds ratio [OR] 2.44, 95% confidence interval [CI] 1.25-4.76 for calcium; OR 3.80, 95% CI 1.79-8.06 for iron). Concurrent consumption of both calcium and iron above these levels was associated with still greater odds of having been diagnosed with glaucoma (OR 7.24, 95% CI 2.42-21.62). A clear dose-response relationship between quintiles of supplementary calcium or iron intake and glaucoma prevalence was not found.These results suggest that there may be a threshold intake of iron and calcium above which there is an increased risk of development of glaucoma. Prospective longitudinal studies are needed, to assess whether oxidant intake is a risk factor for development and progression of glaucoma.

    View details for DOI 10.1167/iovs.11-9038

    View details for Web of Science ID 000302788600024

    View details for PubMedID 22247455

  • Open-angle Glaucoma in Filipino and White Americans: A Comparative Study. Journal of glaucoma Sáles, C. S., Lee, R. Y., Agadzi, A. K., Hee, M. R., Singh, K., Lin, S. C. 2012

    Abstract

    PURPOSE:: To compare the frequency of open-angle glaucoma (OAG) subtypes between Filipino and white Americans in a general ophthalmology clinic population. PATIENTS AND METHODS:: In this retrospective cross-sectional epidemiologic study with prospective sampling, medical charts of 1113 patients aged 40 years or older (513 Filipinos, 600 whites) seen in 2008 were randomly sampled from 2 private comprehensive ophthalmology clinics. Glaucoma was diagnosed based on optic nerve appearance, visual field defects, and other ocular findings using the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) scheme. The normal-tension subtype of OAG [normal-tension glaucoma (NTG)] was defined by intraocular pressure ?21 mm Hg as determined by review of medical records. RESULTS:: NTG comprised a greater proportion of all glaucomatous disease in Filipino subjects [Filipino (F) vs. white (W): 46.7% vs. 26.8%; P=0.02]. Filipinos were more commonly diagnosed with OAG and NTG than whites (F vs. W: OAG, 11.9% vs. 8.2%; NTG, 6.8% vs. 2.5%; P=0.04, 0.001, respectively). There was no significant difference in central corneal thickness between Filipino and white subjects with NTG (P=0.66). CONCLUSIONS:: Both OAG and NTG may be more common in Filipino Americans than in white Americans with the propensity for NTG being particularly high in the former relative to the latter group.

    View details for PubMedID 23221903

  • Laser Trabeculoplasty for Open-Angle Glaucoma OPHTHALMOLOGY Samples, J. R., Singh, K., Lin, S. C., Francis, B. A., Hodapp, E., Jampel, H. D., Smith, S. D. 2011; 118 (11): 2296-2302

    Abstract

    To provide an evidence-based summary of the outcomes, repeatability, and safety of laser trabeculoplasty for open-angle glaucoma.A search of the peer-reviewed literature in the PubMed and the Cochrane Library databases was conducted in June 2008 and was last repeated in March 2010 with no date or language restrictions. The search yielded 637 unique citations, of which 145 were considered to be of possible clinical relevance for further review and were included in the evidence analysis.Level I evidence indicates an acceptable long-term efficacy of initial argon laser trabeculoplasty for open-angle glaucoma compared with initial medical treatment. Among the remaining studies, level II evidence supports the efficacy of selective laser trabeculoplasty for lowering intraocular pressure for patients with open-angle glaucoma. Level III evidence supports the efficacy of repeat use of laser trabeculoplasty.Laser trabeculoplasty is successful in lowering intraocular pressure for patients with open-angle glaucoma. At this time, there is no literature establishing the superiority of any particular form of laser trabeculoplasty. The theories of action of laser trabeculoplasty are not elucidated fully. Further research into the differences among the lasers used in trabeculoplasty, the repeatability of the procedure, and techniques of treatment is necessary.Proprietary or commercial disclosure may be found after the references.

    View details for DOI 10.1016/j.ophtha.2011.04.037

    View details for Web of Science ID 000296573500027

    View details for PubMedID 21849211

  • Intraocular Pressure Variability and Glaucoma Risk Complex and Controversial ARCHIVES OF OPHTHALMOLOGY Singh, K., Sit, A. J. 2011; 129 (8): 1080-1081
  • Novel Glaucoma Procedures A Report by the American Academy of Ophthalmology OPHTHALMOLOGY Francis, B. A., Singh, K., Lin, S. C., Hodapp, E., Jampel, H. D., Samples, J. R., Smith, S. D. 2011; 118 (7): 1466-1480

    Abstract

    To review the published literature and summarize clinically relevant information about novel, or emerging, surgical techniques for the treatment of open-angle glaucoma and to describe the devices and procedures in proper context of the appropriate patient population, theoretic effects, advantages, and disadvantages.Devices and procedures that have US Food and Drug Administration clearance or are currently in phase III clinical trials in the United States are included: the Fugo blade (Medisurg Ltd., Norristown, PA), Ex-PRESS mini glaucoma shunt (Alcon, Inc., Hunenberg, Switzerland), SOLX Gold Shunt (SOLX Ltd., Boston, MA), excimer laser trabeculotomy (AIDA, Glautec AG, Nurnberg, Germany), canaloplasty (iScience Interventional Corp., Menlo Park, CA), trabeculotomy by internal approach (Trabectome, NeoMedix, Inc., Tustin, CA), and trabecular micro-bypass stent (iStent, Glaukos Corporation, Laguna Hills, CA).Literature searches of the PubMed and the Cochrane Library databases were conducted up to October 2009 with no date or language restrictions.These searches retrieved 192 citations, of which 23 were deemed topically relevant and rated for quality of evidence by the panel methodologist. All studies but one, which was rated as level II evidence, were rated as level III evidence.All of the devices studied showed a statistically significant reduction in intraocular pressure and, in some cases, glaucoma medication use. The success and failure definitions varied among studies, as did the calculated rates. Various types and rates of complications were reported depending on the surgical technique. On the basis of the review of the literature and mechanism of action, the authors also summarized theoretic advantages and disadvantages of each surgery.The novel glaucoma surgeries studied all show some promise as alternative treatments to lower intraocular pressure in the treatment of open-angle glaucoma. It is not possible to conclude whether these novel procedures are superior, equal to, or inferior to surgery such as trabeculectomy or to one another. The studies provide the basis for future comparative or randomized trials of existing glaucoma surgical techniques and other novel procedures.

    View details for DOI 10.1016/j.ophtha.2011.03.028

    View details for Web of Science ID 000292303000035

    View details for PubMedID 21724045

  • Central corneal thickness and related factors in an elderly American Chinese population CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY Wang, D., Singh, K., Weinreb, R., Kempen, J., He, M., Lin, S. 2011; 39 (5): 412-420

    Abstract

    To assess central corneal thickness and related factors in an elderly American Chinese population residing in San Francisco.Cross-sectional community based study.American Chinese aged 40 years and older were enrolled using random cluster sampling and volunteer screening in the Chinatown district of San Francisco.The following data were obtained: central corneal thickness by ultrasound pachymetry, intraocular pressure by Goldmann applanation tonometry, axial length by A-scan biometry, refractive status and corneal curvature by autorefractor. History of systemic and ocular diseases was collected via standard questionnaire.Central corneal thickness.Of 311 eligible subjects, 274 consented to study participation, and 228 phakic eyes were analyzed. Mean corneal thickness was 524.1 ± 31.1 µm, 545.5 ± 30.9 µm and 538.9 ± 31.8 µm in the sampling cluster, volunteer group and all subjects, respectively. A multiple linear regression model showed corneal thickness to be negatively associated with age (standardized regression coefficient [SRC] = -0.21; P = 0.016) and corneal curvature (SRC = -0.19; P = 0.018) but positively correlated with intraocular pressure (SRC = 0.20; P = 0.023).The distribution of central corneal thickness among this American Chinese population is similar to that reported in studies from East Asia. The independent factors associated with thinner corneas included older age, lower intraocular pressure and greater corneal curvature. While descendents of Chinese immigrants in America have, on average, thicker corneas than their ancestors, this phenomenon is potentially impacted by the level of intraocular pressure.

    View details for DOI 10.1111/j.1442-9071.2010.02472.x

    View details for Web of Science ID 000292650600007

    View details for PubMedID 21105973

  • Racial and Ethnic Disparities in Adherence to Glaucoma Follow-up Visits in a County Hospital Population ARCHIVES OF OPHTHALMOLOGY Murakami, Y., Lee, B. W., Duncan, M., Kao, A., Huang, J., Singh, K., Lin, S. C. 2011; 129 (7): 872-878

    Abstract

    To identify predictors of inconsistent attendance at glaucoma follow-up visits in a county hospital population.Prospective recruitment from August 1, 2008, through January 31, 2009, of 152 individuals with glaucoma, with 1-to-1 matching of patients (those with inconsistent follow-up) and controls (those with consistent follow-up). Data were collected via oral questionnaire. Survey results were correlated with attendance at follow-up examinations, using the t test, ?(2) test, and multivariate stepwise logistic regression analysis to calculate the odds ratios (ORs) and 95% confidence intervals.After adjusting for covariates in the logistic regression analysis, factors independently associated with inconsistent follow-up included black race (adjusted OR, 7.16; 95% confidence interval, 1.64-31.24), Latino ethnicity (adjusted OR, 4.77; 1.12-20.29), unfamiliarity with necessary treatment duration (adjusted OR, 3.54; 1.26-9.94), lack of knowledge of the permanency of glaucoma-induced vision loss (adjusted OR, 3.09; 1.18-8.04), and perception that it is not important to attend all follow-up visits (adjusted OR, 3.54; 1.26-9.94).Demographic factors, including race and ethnicity, may directly or indirectly affect adherence to recommended glaucoma follow-up visits. Lack of information regarding irreversible vision loss from glaucoma, need for lifelong treatment, and lack of visual symptoms may be significant barriers to follow-up in this population. Targeted glaucoma education by physicians may improve follow-up, thereby decreasing the morbidity associated with glaucomatous disease.

    View details for Web of Science ID 000292604000005

    View details for PubMedID 21746977

  • Interpretation and misinterpretation of results from the tube versus trabeculectomy study. International ophthalmology clinics Singh, K., Gedde, S. J. 2011; 51 (3): 141-154

    View details for DOI 10.1097/IIO.0b013e31821e542e

    View details for PubMedID 21633244

  • Assessment of visual function in glaucoma: a report by the American Academy of Ophthalmology. Ophthalmology Jampel, H. D., Singh, K., Lin, S. C., Chen, T. C., Francis, B. A., Hodapp, E., Samples, J. R., Smith, S. D. 2011; 118 (5): 986-1002

    Abstract

    To review the published literature to summarize and evaluate the effectiveness of visual function tests in diagnosing glaucoma and in monitoring progression.Literature searches of the PubMed and Cochrane Library databases were conducted last on May 7, 2010, and were restricted to citations published on or after January 1, 1994. The search yielded 1063 unique citations. The first author reviewed the titles and abstracts of these articles and selected 185 of possible clinical relevance for further review. The panel members reviewed the full text of these articles and determined that 85 met inclusion criteria. They conducted data abstraction of the 85 studies, and the panel methodologist assigned a level of evidence to each of the selected articles. One study was rated as level I evidence. The remaining articles were classified broadly as providing level II evidence. Studies deemed to provide level III evidence were not included in the assessment.Standard white-on-white automated perimetry remains the most commonly performed test for assessing the visual field, with the Swedish interactive threshold algorithm (SITA) largely replacing full-threshold testing strategies. Frequency-doubling technology and its refinement into Matrix perimetry, as well as short-wavelength automated perimetry, now available with SITA, have been evaluated extensively. Machine learning classifiers seem to be ready for incorporation into software to help distinguish glaucomatous from nonglaucomatous fields. Other technologies, such as multifocal visual-evoked potential and electroretinography, which were designed as objective measures of visual function, provide testing free of patient input, but issues prevent their adoption for glaucoma management.Advances in technology and analytic tools over the past decade have provided us with more rapid and varied ways of assessing visual function in glaucoma, but they have yet to produce definitive guidance on the diagnosis of glaucoma or its progression over time. Further research on an objective measure of visual function is needed.

    View details for DOI 10.1016/j.ophtha.2011.03.019

    View details for PubMedID 21539982

  • Treatment Outcomes in the Ahmed Baerveldt Comparison Study after 1 Year of Follow-up OPHTHALMOLOGY Budenz, D. L., Barton, K., Feuer, W. J., Schiffman, J., Costa, V. P., Godfrey, D. G., Buys, Y. M. 2011; 118 (3): 443-452

    Abstract

    To determine the relative efficacy and complications of the Ahmed glaucoma valve (AGV) model FP7 (New World Medical, Ranchos Cucamonga, CA) and the Baerveldt glaucoma implant (BGI) model 101-350 (Abbott Medical Optics, Abbott Park, IL) in refractory glaucoma.Multicenter, randomized, controlled clinical trial.Two hundred seventy-six patients, including 143 in the AGV group and 133 in the BGI group.Patients 18 to 85 years of age with refractory glaucoma having intraocular pressure (IOP) of 18 mmHg or more in whom an aqueous shunt was planned were randomized to undergo implantation of either an AGV or a BGI.The primary outcome was failure, defined as IOP >21 mmHg or not reduced by 20% from baseline, IOP ?5 mmHg, reoperation for glaucoma or removal of implant, or loss of light perception vision. Secondary outcomes included mean IOP, visual acuity, use of supplemental medical therapy, and complications.Preoperative IOP (mean±standard deviation [SD]) was 31.2±11.2 mmHg in the AGV group and 31.8±12.5 mmHg in the BGI group (P = 0.71). At 1 year, mean±SD IOP was 15.4±5.5 mmHg in the AGV group and 13.2±6.8 mmHg in the BGI group (P = 0.007). The mean±SD number of glaucoma medications was 1.8±1.3 in the AGV group and 1.5±1.4 in the BGI group (P = 0.071). The cumulative probability of failure was 16.4% (standard error [SE], 3.1%) in the AGV group and 14.0% (SE, 3.1%) in the BGI group at 1 year (P = 0.52). More patients experienced early postoperative complications in the BGI group (n = 77; 58%) compared with the AGV group (n = 61; 43%; P = 0.016). Serious postoperative complications associated with reoperation, vision loss of ?2 Snellen lines, or both occurred in 29 patients (20%) in the AGV group and in 45 patients (34%) in the BGI group (P = 0.014).Although the average IOP after 1 year was slightly higher in patients who received an AGV, there were fewer early and serious postoperative complications associated with the use of the AGV than the BGI.

    View details for DOI 10.1016/j.ophtha.2010.07.016

    View details for Web of Science ID 000287964400004

    View details for PubMedID 20932583

  • The Ahmed Baerveldt Comparison Study Methodology, Baseline Patient Characteristics, and Intraoperative Complications OPHTHALMOLOGY Barton, K., Gedde, S. J., Budenz, D. L., Feuer, W. J., Schiffman, J. 2011; 118 (3): 435-442

    Abstract

    The Ahmed Baerveldt Comparison (ABC) Study compares the long-term outcomes and complications of the Ahmed glaucoma valve (AGV; model FP7; New World Medical, Los Ranchos, CA) and the Baerveldt glaucoma implant (BGI; model 101-350; Abbott Medical Optics, Abbott Park, IL).Multicenter, randomized, controlled clinical trial.Two hundred seventy-six glaucoma patients at 16 clinical centers worldwide who were 18 to 85 years of age with inadequately controlled intraocular pressure (IOP; ?18 mmHg) in whom placement of an aqueous shunt was planned.Study patients were randomized to undergo implantation of an AGV or a BGI.Failure, defined as IOP >21 mmHg or not reduced by 20% less than baseline or IOP ?5 mmHg (2 consecutive visits after 3 months), additional glaucoma surgery, removal of the implant, or loss of light perception vision.A total of 276 patients were enrolled between October 2006 and April 2008, including 143 in the AGV group and 133 in the BGI group. The mean age±standard deviation (SD) of patients enrolled was 63±14 years, and 52% were male. The mean baseline IOP±SD was 31.5±11.8 mmHg. Except for a 13% higher prevalence of hypertension in the AGV group, no significant differences in baseline demographic or ocular characteristics were observed between the study groups. Intraoperative complications occurred in 11 (8%) patients in the AGV group and in 16 (12%) patients in the BGI group (P = 0.31).The ABC Study should yield valuable prospective data comparing 2 commonly used aqueous shunts in clinical practice.

    View details for DOI 10.1016/j.ophtha.2010.07.015

    View details for Web of Science ID 000287964400003

    View details for PubMedID 20932581

  • Medical management of glaucoma: principles and practice. Indian journal of ophthalmology Singh, K., Shrivastava, A. 2011; 59: S88-92

    Abstract

    Glaucoma care is more an art than science. The introduction of several new classes of glaucoma medications and the completion of many large randomized clinical trials have not changed this fact. While we now have better choices when initiating glaucoma therapy relative to our predecessors, the principles of glaucoma therapy have not changed much during this period. Debates continue regarding the utility of concepts such as "the monocular therapeutic trial," "target intraocular pressure (IOP)," and "maximal medical therapy." Our tools for detecting and following glaucomatous disease have improved but are not precise enough for us to prospectively predict which patients will do better or worse than others. Much attention has been given to disease stage, rate of progression, and compliance with medications but regular patient follow-up, an area that has received little attention, may be among the most important predictors of patient outcomes.

    View details for DOI 10.4103/0301-4738.73691

    View details for PubMedID 21150040

  • Axial Length Does Not Correlate With Degree of Visual Field Loss in Myopic Chinese Individuals With Glaucomatous Appearing Optic Nerves JOURNAL OF GLAUCOMA Chao, D. L., Shrivastava, A., Kim, D. H., Lin, H., Singh, K. 2010; 19 (8): 509-513

    Abstract

    We previously described a group of patients of Chinese ancestry who presented with optic nerve appearance and visual field loss suggestive of glaucoma but did not show progression characteristic of this disease for up to 7 years. The purpose of this study was to assess whether axial length is a risk factor for visual field loss in patients presenting with this cluster of findings.Twenty patients of Chinese ancestry with characteristics of this previously described condition including myopia, tilted discs, and glaucomatous visual field abnormalities who also had asymmetric visual field loss were enrolled in this study. Patients underwent axial length measurement of both eyes and a fellow eye analysis was performed to determine the relationship between axial length and visual field loss.Tilted discs were found in 30 out of 40 eyes, with cup/disc ratios ranging from 0.5 to 0.9. Myopia >6.00 diopters was also found in 30 out of 40 eyes. In these subjects with disease that was discordant between the 2 eyes, longer axial length was not found to be associated with greater visual field loss (P>0.99, Freeman-Halton extension of the Fisher exact test). No correlation was found between axial length and mean deviation on visual field testing (r=-0.06).We did not find axial length to be a risk factor for visual field loss in eyes with asymmetric disease in this patient population. These findings suggest that factors other than progressive lengthening of the eye play an important role in the etiology of glaucomatous appearing optic nerve damage and visual field loss in this specific subset of patients.

    View details for DOI 10.1097/IJG.0b013e3181d12dae

    View details for Web of Science ID 000282986300003

    View details for PubMedID 20179621

  • Spontaneous Venous Pulsation as a Barometer for Translaminar Pressure Fluctuation JOURNAL OF GLAUCOMA Chang, T. C., Singh, K. 2010; 19 (5): 347-348

    View details for DOI 10.1097/IJG.0b013e3181c29b3f

    View details for Web of Science ID 000279006300015

    View details for PubMedID 20543631

  • The effect of cataract extraction on intraocular pressure CURRENT OPINION IN OPHTHALMOLOGY Shrivastava, A., Singh, K. 2010; 21 (2): 118-122

    Abstract

    To review the current ophthalmic literature regarding the impact of modern cataract surgery on intraocular pressure (IOP).Many articles in the literature demonstrate a modest, long-lasting decrease in IOP following phacoemulsification and posterior chamber intraocular lens implantation in patients with primary open-angle glaucoma and ocular hypertension. The mechanism of this average pressure-lowering effect has yet to be elucidated. The IOP reductions obtained in patients with angle closure glaucoma are often more pronounced than those seen in patients with open angles. Patients with higher levels of preoperative IOP obtain greater average reductions in IOP, although this phenomenon may partially be explained by a statistical effect known as regression to the mean.Although it is well recognized that phacoemulsification may result in a modest sustained reduction in IOP, there are several limitations in the studies that have assessed the magnitude of this effect. The implications of such IOP reduction with cataract surgery on the medical and surgical algorithms for care in patients with open-angle glaucoma and coexistent cataract remain unclear. In contrast, the substantial benefits of cataract surgery in patients with acute and chronic angle-closure glaucoma have been well studied and are generally widely accepted. An improved understanding of the pathophysiological mechanisms of IOP lowering after cataract extraction may help us better predict which patients are most likely to benefit from simple cataract extraction, obviating the need for combined cataract and glaucoma surgical procedures in such circumstances.

    View details for DOI 10.1097/ICU.0b013e3283360ac3

    View details for Web of Science ID 000275063500005

    View details for PubMedID 20040874

  • Review of results from the Tube Versus Trabeculectomy Study CURRENT OPINION IN OPHTHALMOLOGY Gedde, S. J., Heuer, D. K., Parrish, R. K. 2010; 21 (2): 123-128

    Abstract

    The Tube Versus Trabeculectomy (TVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube-shunt surgery to trabeculectomy with mitomycin (MMC) in eyes with previous cataract and/or unsuccessful glaucoma surgery. This article reviews published results from the TVT Study.Tube-shunt surgery had a higher success rate than trabeculectomy with MMC during the first 3 years of follow-up. Trabeculectomy with MMC produced greater intraocular pressure (IOP) reduction in the early postoperative period compared with tube-shunt placement, but similar IOPs were observed after 3 months. Tube-shunt surgery was associated with greater use of adjunctive-medical therapy than trabeculectomy with MMC during the first 2 years of the study, but no difference in medication use was seen at 3 years. The incidence of postoperative complications was higher after trabeculectomy with MMC compared with tube-shunt surgery, but serious complications associated with vision loss and/or reoperation developed with similar frequency after both surgical procedures. No difference in the rate of vision loss was present following trabeculectomy with MMC and tube-shunt surgery after 3 years of follow-up. Cataract progression was common, but occurred with similar frequency with both procedures.Intermediate-term results of the TVT Study support the expanded use of tube shunts beyond refractory glaucomas. Tube-shunt surgery is an appropriate surgical option in patients who have undergone prior cataract and/or unsuccessful filtering surgery.

    View details for DOI 10.1097/ICU.0b013e3283360b68

    View details for Web of Science ID 000275063500006

    View details for PubMedID 20040872

  • Postfiltration Hypotony Maculopathy in Young Chinese Myopic Women With Glaucomatous Appearing Optic Neuropathy JOURNAL OF GLAUCOMA Silva, R. A., Doshi, A., Law, S. K., Singh, K. 2010; 19 (2): 105-110

    Abstract

    To describe management and surgical outcomes of 3 young women of Chinese origin with advanced glaucomatous optic neuropathy.Three 36 to 48-year-old female patients.A retrospective medical records review of 3 Chinese women with prior diagnoses of glaucoma treated with trabeculectomy was performed. Optic nerve imaging and standard automated perimetry were also reviewed. Mean follow-up period was 4 years.All patients had arcuate scotomas bilaterally at the time of initial ophthalmic examination. Two patients were highly myopic (>or= -6.00 diopter spherical equivalent) with tilting of the optic nerve head and parapapillary atrophy. Cup-to-disc ratios ranged from 0.4 to 0.9. Trabeculectomy with mitomycin C was performed in the right eye of all patients with subsequent hypotony related complications requiring surgical treatment. All patients experienced long-term decline in best-corrected visual acuity after trabeculectomy. No patient had a new area of field loss on standard automated perimetry, although the density of the preexisting scotomas increased in the nonoperated eye of all patients.High myopia, optic nerve head tilting, and parapapillary atrophy are likely associated with the increased susceptibility to damage of dependent axons. Axons outside of the area of tilt may be relatively protected. As young myopes are more likely to suffer from hypotony related complications after trabeculectomy, the risk of an increase in preexisting field defect density should be weighed against the risk of long-term vision loss after filtration surgery. The development of a new area of field loss may be an appropriate indication for surgery in some such patients.

    View details for DOI 10.1097/IJG.0b013e3181a98a39

    View details for Web of Science ID 000274915500006

    View details for PubMedID 19661828

  • Three-Year Follow-up of the Tube Versus Trabeculectomy Study AMERICAN JOURNAL OF OPHTHALMOLOGY Gedde, S. J., Schiffman, J. C., Feuer, W. J., Herndon, L. W., Brandt, J. D., Budenz, D. L. 2009; 148 (5): 670-684

    Abstract

    To report 3-year results of the Tube Versus Trabeculectomy (TVT) Study.Multicenter randomized clinical trial.Seventeen clinical centers.Patients 18 to 85 years of age who had previous trabeculectomy, cataract extraction with intraocular lens implantation, or both and uncontrolled glaucoma with intraocular pressure (IOP) > or =18 mm Hg and < or =40 mm Hg on maximum tolerated medical therapy.A 350-mm(2) Baerveldt glaucoma implant or trabeculectomy with mitomycin C (MMC 0.4 mg/ml for 4 minutes).IOP, visual acuity, use of supplemental medical therapy, surgical complications, and failure (IOP >21 mm Hg or not reduced by 20%, IOP < or =5 mm Hg, reoperation for glaucoma, or loss of light perception vision).A total of 212 eyes of 212 patients were enrolled, including 107 in the tube group and 105 in the trabeculectomy group. At 3 years, IOP (mean +/- standard deviation [SD]) was 13.0 +/- 4.9 mm Hg in the tube group and 13.3 +/- 6.8 mm Hg in the trabeculectomy group (P = .78). The number of glaucoma medications (mean +/- SD) was 1.3 +/- 1.3 in the tube group and 1.0 +/- 1.5 in the trabeculectomy group (P = .30). The cumulative probability of failure during the first 3 years of follow-up was 15.1% in the tube group and 30.7% in the trabeculectomy group (P = .010; hazards ratio, 2.2; 95% confidence interval, 1.2 to 4.1). Postoperative complications developed in 42 patients (39%) in the tube group and 63 patients (60%) in the trabeculectomy group (P = .004). Surgical complications were associated with reoperation and/or loss of > or =2 Snellen lines in 24 patients (22%) in the tube group and 28 patients (27%) in the trabeculectomy group (P = .58).Tube shunt surgery had a higher success rate compared to trabeculectomy with MMC during the first 3 years of follow-up in the TVT Study. Both procedures were associated with similar IOP reduction and use of supplemental medical therapy at 3 years. While the incidence of postoperative complications was higher following trabeculectomy with MMC relative to tube shunt surgery, most complications were transient and self-limited.

    View details for DOI 10.1016/j.ajo.2009.06.018

    View details for Web of Science ID 000271669300008

    View details for PubMedID 19674729

  • Intraocular pressure fluctuations: how much do they matter? CURRENT OPINION IN OPHTHALMOLOGY Singh, K., Shrivastava, A. 2009; 20 (2): 84-87

    Abstract

    To review the current literature with regard to the importance of IOP fluctuation/variation as independent risk factors for glaucoma progression.There are conflicting reports in the literature assessing the relative importance of 'intraocular pressure (IOP) fluctuation' and 'mean IOP' as risk factors for glaucoma progression. There has been a trend toward more studies concluding that IOP fluctuation is an important independent risk factor for such progression but there is considerable variability in the quality of such studies. In particular, assumptions regarding causality have created doubt regarding some conclusions. Recent studies have also suggested that we should not abandon mean IOP as the important predictor of glaucoma progression. It should be noted that several analyses pertaining to this subject have emerged from large prospective randomized clinical trials primarily designed to answer other questions.A review of the literature reveals that there is no conclusive evidence that IOP fluctuation/variation are independent risk factors for glaucoma progression. One should not discount the importance of mean IOP as a predictor of such progression. A major factor limiting all analyses pertaining to this issue is the inability to continuously measure IOP and thus optimally assess mean and variability.

    View details for DOI 10.1097/ICU.0b013e328324e6c4

    View details for Web of Science ID 000264201900003

    View details for PubMedID 19248311

  • Motility Disturbances in the Tube Versus Trabeculectomy Study During the First Year of Follow-up AMERICAN JOURNAL OF OPHTHALMOLOGY Rauscher, F. M., Gedde, S. J., Schiffman, J. C., Feuer, W. J., Barton, K., Lee, R. K. 2009; 147 (3): 458-466

    Abstract

    To describe the preoperative and postoperative motility disturbances encountered in the Tube Versus Trabeculectomy (TVT) Study during the first year of follow-up.Multicenter randomized clinical trial.settings: Seventeen clinical centers. population: Patients 18 to 85 years old who had previous trabeculectomy and/or cataract surgery and uncontrolled glaucoma with intraocular pressure > or =18 mm Hg and < or =40 mm Hg on maximum tolerated medical therapy. interventions: 350-mm(2) Baerveldt glaucoma implant or trabeculectomy with mitomycin C (MMC). main outcome measures: Preoperative and postoperative evaluation of ocular motility and diplopia.Motility disturbances were detected in 55 patients (28%) at baseline. New-onset persistent diplopia was reported in 5 patients (5%) in the tube group and no patients in the trabeculectomy group at 1 year (P = .06). A new postoperative motility disturbance developed or worsened in 7 patients (9.9%) in the tube group and no patients in the trabeculectomy group during the first year of follow-up (P = .005). Postoperative motility disturbances were also associated with increasing age (P < .001) and right eye surgery (P = .044).Preoperative motility disturbances were common among patients in the TVT Study. New postoperative motility disturbances were more frequent following tube shunt surgery than trabeculectomy with MMC after 1 year of follow-up.

    View details for DOI 10.1016/j.ajo.2008.09.019

    View details for Web of Science ID 000263659000017

    View details for PubMedID 19038375

  • Glaucomatous Disease in Patients With Normal Pressure Hydrocephalus JOURNAL OF GLAUCOMA Chang, T. C., Singh, K. 2009; 18 (3): 243-246

    Abstract

    To investigate the relative prevalence of glaucomatous disease in patients with normal pressure hydrocephalus (NPH) compared with age-matched non-NPH controls with hydrocephalus.Case-control study.Using International Classification of Diseases (ICD-9) codes, we identified the medical records of 72 NPH cases and 72 age-matched controls with hydrocephalus treated at Stanford University Hospital between 1996 and 2007.All available electronic medical records were reviewed. The diagnosis of NPH was verified based on clinical presentation, neuroimaging results, and opening pressure on initial access to cerebrospinal fluid space. Glaucoma status was determined based on history and prior medical, laser, or surgical intraocular pressure-lowering therapy.The proportion of subjects determined as having glaucomatous disease in cases and controls.The prevalence of glaucoma in NPH cases was estimated to be 18.1% in contrast to 5.6% in controls (chi=5.403, P=0.0201). The average age of NPH cases and non-NPH controls was 75.40+/-13.4 and 73.96+/-9.92 years (mean+/-SD), respectively.We found the prevalence of a glaucoma diagnosis to be 3-fold greater in patients with NPH as compared with age-matched non-NPH controls with hydrocephalus. These findings suggest the possiblity of an association between these 2 neurodegenerative diseases which should be studied prospectively.

    View details for Web of Science ID 000264408400016

    View details for PubMedID 19295381

  • Intraocular Pressure: Does it Measure Up? The open ophthalmology journal Wilson, M. R., Singh, K. 2009; 3: 32-37

    Abstract

    The relationship between intraocular pressure (IOP) and glaucoma is complex and not fully understood. We question the validity of several claims relating to the IOP-glaucoma relationship: (1) that 12 mm Hg is an important target in IOP control; (2) that IOP variability is an important risk factor for glaucoma progression; and (3) that every millimeter of mercury of IOP lowering reduces the risk of glaucoma progression by some specific percentage amount. Further, IOP is generally accepted to be an important - if not most important - risk factor for glaucoma development and progression. Using measures of treatment effect - absolute risk reduction, relative risk, and relative risk reduction - we compare the strength of IOP as a risk factor to the strength of a cardiac risk factor in cardiovascular disease.

    View details for DOI 10.2174/1874364100903020032

    View details for PubMedID 19812717

  • Is the patient getting worse? The open ophthalmology journal Singh, K. 2009; 3: 65-66

    Abstract

    Glaucoma care today is often simplified into all or nothing terms with the assumption that if the patient's intraocular pressure (IOP) is above a certain level, glaucomatous disease will progress and when the IOP is lowered to below a threshold, no further progression will occur. This dogma is largely the result of limitations in the resolution of tools currently available to judge progression. Glaucoma is a neurodegenerative disease and, as with all degenerative diseases, progression continues to occur, albeit at slower rates, with appropriate treatment. In the future, as our tools to assess structural and functional optic nerve change become more precise, we will no longer think of glaucoma as being stable or progressive but rather speak in terms of rates of progression.

    View details for DOI 10.2174/1874364100903020065

    View details for PubMedID 19834562

  • Early Aggressive Intraocular Pressure Lowering, Target Intraocular Pressure, and a Novel Concept for Glaucoma Care SURVEY OF OPHTHALMOLOGY Singh, K., Shrivastava, A. 2008; 53: S33-S38

    Abstract

    Early diagnosis of glaucomatous optic nerve damage offers the potential for early treatment which may prevent vision loss from this neurodegenerative disease. Even in patients who do not begin early treatment, early diagnosis allows for better monitoring of disease at a stage where the stakes are lower relative to later stages of the disease. For these reasons, early diagnosis of glaucomatous optic nerve disease is desirable and opens the door for appropriately aggressive therapy. The target intraocular pressure (IOP) concept is widely employed by glaucoma practitioners. Although there have been no randomized clinical trials or other high-quality studies showing the benefits of setting a target IOP versus not using this approach, there is ample evidence that lowering IOP slows glaucoma progression and, in general, lower is better, regardless of disease stage and baseline IOP level. We propose an alternative approach to managing glaucoma without the use of the target IOP concept and suggest that this market IOP concept should be compared with the target IOP approach in an appropriately powered comparative clinical trial.

    View details for DOI 10.1016/j.survophthal.2008.08.007

    View details for Web of Science ID 000261587400005

    View details for PubMedID 19038622

  • Long-term Comparison of Primary Trabeculectomy With 5-Fluorouracil Versus Mitomycin C in West Africa JOURNAL OF GLAUCOMA Kim, H. Y., Egbert, P. R., Singh, K. 2008; 17 (7): 578-583

    Abstract

    To compare the long-term efficacy and safety of intraoperative 5-fluorouracil (5-FU) versus mitomycin-C (MMC) used adjunctively with primary trabeculectomy in a Black West African population.Retrospective comparative study supplemented with cross-sectional follow-up data.Review of 68 eyes of 68 Black West African subjects that underwent primary trabeculectomy with the use of intraoperative 5-FU or MMC between January 1, 1988 and January 1, 2002 and had at least 3 years postoperative follow-up. Postoperative outcome measures included intraocular pressure (IOP) control, number of glaucoma medications, visual acuity, and complications.Thirty-eight of sixty-eight eyes received 5-FU and 30 received MMC. Mean postoperative follow-up was 7.5 and 6.5 years in the 5-FU and MMC groups, respectively (P=0.17). A higher proportion of eyes in the MMC group achieved "qualified" (with or without medical therapy) success with varying IOP targets relative to the 5-FU group, but the differences were not statistically significant. "Complete" (without medical therapy) postoperative success was greater in the MMC group with a significantly higher proportion achieving an IOP <21 mm Hg (P=0.02). MMC use was also associated with a lower likelihood of receiving IOP-lowering medications postoperatively (P=0.01). Baseline demographic characteristics, preoperative and postoperative IOP, visual acuity, and complications did not differ significantly between the 2 groups.Intraoperative MMC use is associated with a lower likelihood of requiring postoperative medications and a greater likelihood of achieving IOP lowering without medications relative to the use of 5-FU in a Black West African population.

    View details for Web of Science ID 000260317800013

    View details for PubMedID 18854737

  • Predictors of and barriers associated with poor follow-up in patients with glaucoma in South India ARCHIVES OF OPHTHALMOLOGY Lee, B. W., Sathyam, P., John, R. K., Singh, K., Robin, A. L. 2008; 126 (10): 1448-1454

    Abstract

    To determine predictors of and reasons for poor longitudinal glaucoma follow-up in South India.This 1-to-1, matched, case-control study enrolled 300 patients with established glaucoma. We defined cases (poor follow-up) and controls (good follow-up) based on number of and maximum interval between glaucoma follow-up visits attended in the preceding year. We collected data by oral questionnaire and used stepwise multivariate logistic regression to calculate odds ratios (ORs) for poor follow-up.Adjusting for age and sex, independent predictors of poor follow-up included lack of formal education (adjusted OR, 4.13; 95% confidence interval [CI], 1.44-11.90), no use of prescribed glaucoma medications (adjusted OR, 2.17; 95% CI, 1.06-4.43), and belief that follow-up is less important if one uses glaucoma medications and has no noticeable visual changes (adjusted OR, 10.59; 95% CI, 3.74-29.97). Age, sex, and disease severity were not significant predictors. The most prevalent barriers to follow-up were belief that there was no problem with one's eyes (44.4%) and lack of escort (19.7%).Knowing predictors of poor follow-up can help identify patients who need individualized strategies to improve follow-up. Because believing one's eyes are problem-free and lacking escorts are significant barriers to follow-up, novel strategies in patient education (eg, intensive counseling, audiovisual aides, and patient support groups) and escort provision may improve longitudinal glaucoma follow-up and disease management.

    View details for Web of Science ID 000259900700017

    View details for PubMedID 18852425

  • Prospective comparison of topical moxifloxacin in eliminating conjunctival bacterial flora following a one-day or one-hour application JOURNAL OF OCULAR PHARMACOLOGY AND THERAPEUTICS Ta, C. N., Chan, I., Dhatt, H. S., Paterno, J., Fisher, E., Singh, K., Montague, A., Egbert, P. R., Cockerham, G., de Kaspar, H. M. 2008; 24 (4): 427-431

    Abstract

    The aim of this study was to compare the efficacy of a 1-hour(h) versus 1-day application of topical moxifloxacin in eliminating conjunctival bacterial flora.In this prospective, nonrandomized, controlled trial, the surgical eyes of 60 patients scheduled for intraocular surgery received topical moxifloxacin four times a day, starting 1 day prior to surgery and three additional applications at 5-minute intervals 1 h before surgery. The nonsurgical eye of each patient only received three applications of the same antibiotic at 5-minute intervals 1 h before surgery. Conjunctival cultures were obtained at baseline and after antibiotic application.Prior to antibiotic application, 80% of surgical eyes and 70% of nonsurgical eyes had positive cultures. Following the 1-day application, significantly fewer eyes (40%) had positive cultures (P < 0.0001), with a further reduction to 32% with three additional doses 1 h prior to surgery. In the nonsurgical eye, the decrease in the percentage of positive cultures, from 55% to 53% following the three applications 1 h prior to surgery, was not significant (P > 0.9999). The 1-day application was associated with significantly fewer positive cultures, compared to the 1-h group (P = 0.0267).The one-day application of moxifloxacin resulted in significantly fewer positive conjunctival cultures, compared with a 1-h application.

    View details for DOI 10.1089/jop.2008.0018

    View details for Web of Science ID 000258731100011

    View details for PubMedID 18665815

  • A panel assessment of glaucoma management: Modification of existing RAND-like methodology for consensus in ophthalmology. Part II: Results and interpretation AMERICAN JOURNAL OF OPHTHALMOLOGY Singh, K., Lee, B. L., Wilson, M. R. 2008; 145 (3): 575-581

    Abstract

    To present the results of a panel consensus assessment of evaluation and therapy relating to primary open-angle glaucoma based on available evidence and expert opinion.A panel consensus assessment of glaucoma diagnosis and therapy using a modified RAND-like appropriateness methodology.One hundred and forty-eight questions, most of which related to glaucoma therapy, were created by a core nonvoting executive committee based on common clinical questions. An evidence-based review of the literature pertaining to these questions was provided to 10 voting panelists. These panelists, who did not participate in either the creation of the questions or the conduct of the literature review, then were polled using a modified technique derived from existing methodology.Consensus agreement or disagreement was reached for 55.4% and 74.3% of the polling statements before and after the panel meeting, respectively. This represents a consensus agreement or disagreement on a majority of polling statements both before and after a meeting of all panelists and the two co-chairs of the program. There was an increase in the proportion of statements where consensus agreement was reached after the panel meeting.Given the paucity of high-quality evidence relating to many of the issues addressed in this assessment and the variability of practice patterns among ophthalmologists, consensus agreement or disagreement was reached for a high proportion of polling statements.

    View details for DOI 10.1016/j.ajo.2007.10.009

    View details for Web of Science ID 000253841900029

    View details for PubMedID 18191098

  • Aqueous Shunts in Glaucoma: a report by the American Accademy of Ophthalmology Ophthalmology Minckler DS, Francis BA, Hodapp EA, Jampel HD, Lin SL, Samples JR, Smith S, Singh K 2008; 115 (6): 1089-98
  • Early Aggressive Intraocular Pressure Lowering, Target Intraocular Pressure and a Novel Concept for Glaucoma Care Survey of Ophthalmology Singh K, Shrivastava A. 2008; 53 (1): S33-38
  • An Expert Panel Assessment of Glaucoma Therapy: Modification of Existing RAND-Like Methodology for Consensus in Ophthalmology. Part I: Methodology and Design American Journal of Ophthalmology Wilson MR, Lee P, Weinreb RN, Lee B, Singh K, the Glaucoma Modified RAND-Like Methodology Group 2008; 145 (3): 570-574
  • Normal Tension Glaucoma: A Different Disease? Journal of Current Glaucoma Practice Singh, K. 2008; 2 (3): 1-3
  • Prospective Comparative Evaluation of Povidone-Iodine (10% for 5 minutes versus 5% for 1 minute) as Prophylaxis For Ophthalmic Surgery J. Cataract and Refract Surg Ta CN, Egbert PR, Singh K, Miño De Kaspar H 2008; 34 (1): 171-172
  • Comparison of One-Day Versus One-Hour Application of Topical Gatifloxacin in Eliminating Conjunctival Bacterial Flora Ophthalmology Moss MJ, Nguyen D, Liu IY, Singh K, Montague A, Egbert RP, De Kaspar MH, Ta NC 2008; 115 (11): 2013-2016
  • Comparison of the ocular hypotensive efficacy of adjunctive brimonidine 0.15% or brinzolamide 1% in combination with travoprost 0.004% OPHTHALMOLOGY Feldman, R. M., Tanna, A. P., Gross, R. L., Chuang, A. Z., Baker, L., Reynolds, A., Prager, T. C. 2007; 114 (7): 1248-1254

    Abstract

    To compare efficacies of adjunctive therapy with brimonidine 0.15% and adjunctive therapy with brinzolamide 1% in combination with travoprost 0.004%.Three-month randomized, parallel-group, double-masked, multicenter clinical trial.Patients with primary open-angle glaucoma, exfoliation glaucoma, or ocular hypertension with intraocular pressure (IOP) > 18 mmHg on monotherapy with travoprost (N = 163).Patients were randomized to receive adjunctive therapy with twice-daily brimonidine (N = 79) or twice-daily brinzolamide (N = 84). Treatment efficacy was assessed after 1 and 3 months of combination therapy. Intraocular pressure was measured at 8 am, noon, and 4 pm at baseline (on travoprost monotherapy) and after 3 months of combination therapy. Mean diurnal IOP was defined as the average of the IOP measurements at these 3 time points. Adverse events were recorded at each visit.Difference between treatment groups in mean diurnal IOP at month 3, adjusted for difference in baseline IOP, using analysis of covariance.Mean diurnal IOPs (+/- standard error of the mean) at baseline were 21.7+/-0.33 mmHg in the brimonidine group and 21.1+/-0.29 mmHg in the brinzolamide group (P = 0.16). Mean diurnal IOPs at month 3 were 19.6+/-0.41 mmHg in the brimonidine group and 18.4+/-0.33 mm Hg in the brinzolamide group (P = 0.019). At month 3, mean diurnal IOPs, adjusted for difference in baseline IOP, were 19.3+/-0.27 in the brimonidine group and 18.6+/-0.25 in the brinzolamide group (P = 0.035).The combination of travoprost and brinzolamide was statistically significantly more efficacious than the combination of travoprost and brimonidine in lowering IOP. The clinical significance of this difference is uncertain.

    View details for DOI 10.1016/j.ophtha.2007.03.012

    View details for Web of Science ID 000247629700003

    View details for PubMedID 17509688

  • Cost-effective evaluation of the glaucoma suspect CURRENT OPINION IN OPHTHALMOLOGY Doshi, A., Singh, K. 2007; 18 (2): 97-103

    Abstract

    The number of glaucoma patients nationwide will increase appreciably over the coming years reflecting the increased number of elderly people. This increase will require efficient allocation of available healthcare resources for management of the entire spectrum of disease from glaucoma suspect to advanced glaucoma. This review considers the cost-effective management of glaucoma suspects.Medications account for the majority of costs of managing glaucoma suspects while the cost of clinical evaluations has remained stable. Early disease recognition limits both direct and indirect costs. Risk stratification of glaucoma suspects can identify those who would benefit most from therapy. Newer structural modalities can be as predictive of early disease progression as stereo disk photography. Short-wavelength automated perimetry and frequency doubling technology may be more appropriate in confirming field changes in this patient population.Overall costs of managing glaucoma can be limited by preventing early disease progression. Identification and monitoring of glaucoma suspects would help minimize overall costs if intraocular pressure lowering therapy is reserved for high-risk glaucoma suspects or those with early disease. Yet, since the rate of progression to blindness for a particular patient is not known, the most cost-effective time to begin intraocular pressure lowering therapy remains unclear.

    View details for Web of Science ID 000244444000001

    View details for PubMedID 17301609

  • Nonprogressive glaucomatous cupping and visual field abnormalities in young Chinese males OPHTHALMOLOGY Doshi, A., Kreidl, K. O., Lombardi, L., Sakamoto, D. K., Singh, K. 2007; 114 (3): 472-479

    Abstract

    To describe a series of young to middle-aged men of Chinese origin who presented with a constellation of ocular findings suggestive of glaucoma, that were found to be stable over a 7-year period.Retrospective case series.Sixteen 25- to 66-year-old male patients.Medical records of the participants, of Chinese origin and referred for glaucoma evaluation over a 7-year period, were reviewed. All patients underwent complete ophthalmic examinations, stereo imaging of the optic nerves, and automated perimetry. Fewer than 5% of all patients seen in this practice were of Chinese origin. The patients were observed for the duration of the study in a single glaucoma clinic.Visual field (VF) changes or progressive optic nerve cupping suggestive of glaucoma.The patients had an average age of 38.9 years. Tilted discs were present in 75.0% (24/32) and peripapillary atrophy in 81.3% (26/32) of nerves. Cup-to-disc ratios ranged from 0.20 to 0.95 and averaged 0.56. The lowest intraocular pressure (IOP) in any patient at any time was 8 mmHg, whereas the highest was 29 (average range, 13.5-17.9). Intraocular pressure-lowering therapy had been used in 56.3% (9/16). There was a family history of presumed glaucoma in 25.0% (4/16) of patients. High myopia (>-6.00-diopter spherical equivalent [SE]) was present in 43.8% of eyes (14/32), and SEs ranged from -11.25 to +0.25. The most common VF defect was an arcuate defect, found in 31.3% (10/32) of patients. There were no females of Chinese origin with similar findings identified during this period. Neither optic nerve nor significant VF progression was found during the follow-up period, regardless of the use of IOP-lowering therapy.These young Chinese patients previously diagnosed with glaucoma or considered glaucoma suspects had stable ocular findings for up to 7 years, irrespective of IOP-lowering therapy. Their condition was associated with myopia and tilted discs. Many were being treated with IOP-lowering therapy for glaucoma, a condition they may not have had. Further prospective epidemiologic study is needed to determine whether such a constellation of nonprogressive findings is more common in young Chinese males than in the general population.

    View details for DOI 10.1016/j.ophtha.2006.07.036

    View details for Web of Science ID 000244532800013

    View details for PubMedID 17123617

  • Optic Nerve Head and Retinal Nerve Fiber Layer Analysis Ophthalmology Lin SL, Singh K, Dueker DK, Fechtner RD, Minckler DS, Samples JR, Schuman JS 2007; 114 (10): 1937-1949
  • Criteria for Choosing Clinically Effective Glaucoma Treatment Current Therapeutic Research Thygeson J, Burk R, Carassa R, Crichton A, Goni FJ, Menage M, Miglior S, Montgomery D, Nordmann JP, Roberts T, Singh K 2007; 68 (3)
  • Long-Term IOP Fluctuation May Not Be As Important As Previously Reported International Glaucoma Review Singh, K. 2007; 9 (1)
  • Treatment Outcomes in the Tube vs Trabeculectomy Study After One Year of Follow-Up American Journal of Ophthalmology Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL, the Tube Versus Trabeculectomy Study Gr 2007; 143 (1): 9-22
  • Corneal Thickness Measurement in the Management of Primary Open Angle Glaucoma. Ophthalmology Dueker DK, Singh K, Fechtner RD, Lin SL, Minckler DS, Samples JR, Schuman JS 2007; 114 (9): 1779-1787
  • Surgical Complications in the Tube vs Trabeculectomy Study During the First Year of Follow-Up American Journal of Ophthalmology Gedde SJ, Herndon LW, Brandt JD, Budenz DL, Feuer WJ, Schiffman JC, the Tube Versus Trabeculectomy Study Group 2007; 143 (1): 23-31
  • A Blink at Diagnosing Glaucoma Suggests that More May Be Less Ophthalmology Singh K, Van Buskirk EM, Spaeth G 2007; 114 (7): 1239-1240
  • Prospective Randomized comparison of 2 different methods of 5% povidone-lodine applications for anterior segment, Intraocular surgery ARCHIVES OF OPHTHALMOLOGY de Kaspar, H. M., Chang, R. T., Singh, K., Egbert, P. R., Blumenkranz, M. S., Ta, C. N. 2005; 123 (2): 161-165

    Abstract

    To determine the efficacy of reducing conjunctival bacteria flora with 2 different regimens of 5% povidone-iodine application: 2 drops on the conjunctiva cul-de-sac vs a 10-mL conjunctival irrigation of the fornices.In this prospective controlled trial, 200 eyes undergoing anterior segment intraocular surgery were randomized to control and study groups. All patients from both groups received topical ofloxacin and a povidone-iodine scrub of the periorbital area before the surgical procedure. The eyes in the control group received 2 drops of povidone-iodine on the conjunctiva preoperatively, whereas eyes in the study group had irrigation of the fornices with 10 mL of povidone-iodine. Conjunctival cultures were obtained at 4 separate time points before and after surgery.Twenty (26%) of 78 eyes in the study group had positive conjunctival cultures immediately prior to surgery compared with 40 (43%) of 94 eyes in the control group (P = .02). At the conclusion of the surgery, 14 (18%) of 78 eyes and 30 (32%) of 94 eyes had positive cultures in the study and control groups, respectively (P = .05).Irrigation of the fornices with 5% povidone-iodine was associated with significantly fewer positive conjunctival cultures at the time of surgery compared with the application of 2 drops on the conjunctiva.

    View details for Web of Science ID 000226755000002

  • Prospective Randomized Comparison of 2 Different Methods of 5% Povidone-Iodine Applications for Anterior Segment Intraocular Surgery Archives of Ophthalmolology de Kaspar H, Chang RT, Singh K, Egbert PR, Blumenkranz MS, Ta CN 2005; 123 (2): 161-5
  • The Tube Versus Trabeculectomy Study: Design and Baseline Characteristics of Study Patients American Journal of Ophthalmology Gedde SJ, Schiffman JC, Feuer WJ, Parrish RK 2nd, Heuer DK, Brandt JD, Tube Versus Trabeculectomy Study Group 2005; 140 (2): 275-87
  • Comparison of preoperative conjunctival bacterial flora in patients undergoing glaucoma or cataract surgery JOURNAL OF GLAUCOMA de Kaspar, H. M., Kreidl, K. O., Singh, K., Ta, C. N. 2004; 13 (6): 507-509

    Abstract

    To assess differences in conjunctival bacterial flora between patients undergoing glaucoma and cataract surgery.A prospective study comparing conjunctival bacterial cultures obtained from 339 patients undergoing either cataract (n = 258) or glaucoma (n = 81) surgery. All cultures were acquired during the preoperative visit, approximately three to seven days prior to surgery. The culture samples were inoculated onto blood and chocolate agar, as well as blood culture broth media. All bacterial isolates were identified and statistical analyses were performed to determine if there were differences in flora between the eyes undergoing cataract versus glaucoma surgery.Two hundred fifteen of 258 eyes (83%) undergoing cataract surgery were found to have positive bacterial growth, compared with 62 of 81 eyes (77%) of those undergoing glaucoma surgery (P = 0.2246). Coagulase-negative Staphylococci, the most common bacterial isolate, was cultured from 167 eyes (65%) in the cataract group and 42 (52%) in the glaucoma group (P = 0.0514). Among all bacterial isolates, only Corynebacterium species was found to be statistically different between the two patient groups with 92 (36%) and 11 (14%) eyes testing positive in the cataract and glaucoma groups, respectively (P = 0.0003).There was no statistically significant difference in the proportion of conjunctival culture samples testing positive for bacterial growth in eyes undergoing glaucoma surgery compared with those undergoing cataract surgery. Glaucoma medications, or their preservatives, do not appear to significantly alter conjunctival flora. Techniques used for endophthalmitis prophylaxis prior to cataract surgery are likely appropriate for glaucoma surgery as well.

    View details for Web of Science ID 000225273300014

    View details for PubMedID 15534478

  • Three-day application of topical ofloxacin reduces the contamination rate of microsurgical knives in cataract surgery - A prospective randomized study OPHTHALMOLOGY de Kaspar, H. M., Chang, R. T., Shriver, E. M., Singh, K., Egbert, P. R., Blumenkranz, M. S., Ta, C. N. 2004; 111 (7): 1352-1355

    Abstract

    To determine the rate of contamination of microsurgical knives during cataract surgery and the benefit of a 3-day versus a 1-hour preoperative application of topical ofloxacin in reducing the contamination rate.Prospective, randomized controlled trial.Seventy-eight eyes of 75 patients were randomly assigned to control (39 eyes) or study groups (39 eyes).All patients from both groups received 0.3% topical ofloxacin 1 hour before surgery, 5% povidone-iodine (PVI) scrub of the periorbital area, and 2 drops of PVI onto the ocular surface preoperatively. The patients in the study group also received ofloxacin 4 times a day for 3 days before surgery.Microsurgical knives were placed in blood culture broth media immediately after the incision had been made. The number of positive cultures and types of bacteria isolated were determined.Ten of 39 knives (26%) in the control group were found to be positive for bacterial growth compared with only 2 of 39 (5%) in the study group (P = 0.028).The initial paracentesis incision frequently results in contamination of the microsurgical knife and may serve as a mechanism for introducing bacteria from the ocular surface into the anterior chamber. The application of topical ofloxacin for 3 days before surgery significantly reduces the contamination rate of the microsurgical knives, compared with a preoperative application of ofloxacin given 1 hour before surgery.

    View details for Web of Science ID 000222418900017

    View details for PubMedID 15234136

  • The challenge of determining aqueous contamination rate in anterior segment intraocular surgery AMERICAN JOURNAL OF OPHTHALMOLOGY Ta, C. N., Egbert, P. R., Singh, K., Blumenkranz, M. S., de Kaspar, H. M. 2004; 137 (4): 662-667

    Abstract

    To determine aqueous contamination rate in anterior segment intraocular surgery using two different techniques of obtaining aqueous fluid and to assess whether a 3-day application of topical 0.3% ofloxacin reduces this contamination rate compared with a 1-hour application.Randomized clinical trial.One hundred and thirty-three eyes of 130 patients undergoing anterior segment intraocular surgery were randomized to either control (64 eyes received topical ofloxacin 1 hour before surgery) or study groups (69 eyes received topical ofloxacin four times a day for 3 days before surgery in addition to 1 hour preoperatively). Eyes in both groups received a periorbital iodine scrub and two drops of topical 5% iodine. Aqueous fluid was obtained at the beginning and conclusion of surgery using a cannula passed through a paracentesis or a needle passed through clear cornea. The aqueous, cannula, and needles were inoculated in blood culture media broth and bacterial growth was identified.Overall, eight of 89 aqueous samples (9%) obtained using a cannula at the beginning of surgery were culture-positive. Similarly, six of 41 aqueous samples (15%) obtained through a needle through clear cornea at the beginning of surgery showed contamination. At the conclusion of surgery, nine of 112 samples (8%) showed positive cultures. There was no difference in the aqueous contamination rates between the control and study groups.Despite the use of a needle to obtain aqueous fluid at the beginning of surgery before creating a paracentesis, the aqueous contamination rate remained higher than that found at the conclusion of surgery. A 3-day application of topical ofloxacin before surgery did not reduce the anterior chamber aqueous contamination rate relative to a 1-hour application.

    View details for DOI 10.1016/j.ajo.2003.11.057

    View details for Web of Science ID 000220762800009

    View details for PubMedID 15059705

  • Update on antifibrotic use in glaucoma surgery, including use in trabeculectomy and glaucoma drainage implants and combined cataract and glaucoma surgery. Current opinion in ophthalmology Yoon, P. S., Singh, K. 2004; 15 (2): 141-146

    Abstract

    This paper summarizes the use of antifibrotic agents adjunctive to glaucoma surgery, reviews recently published studies that address current use of these antifibrotics, and reviews new methods of wound modulation.The use of antifibrotic agents, namely, 5-fluorouracil and mitomycin C, in conjunction with glaucoma surgery has resulted in lower postoperative intraocular pressures after trabeculectomy or combined cataract and glaucoma surgery. Mixed results have been seen when these agents are used with glaucoma drainage device surgery. The use of antifibrotic agents has also created and increased complications. Therefore, methods of antifibrotic use have become more refined and modified for specific circumstances. Promising new wound modulation agents, such as CAT-152, are currently under study.Antifibrotics are potent adjuncts to glaucoma surgery, but along with their beneficial use are risks that need to be considered. While we continue to look for more efficacious agents and methods to treat glaucoma, we must continue to modify techniques with the individual patient's best interest in mind.

    View details for PubMedID 15021227

  • Risk Assessment in the Management of Patients With Ocular Hypertension American Journal of Ophthalmology Weinreb RN, Friedman DS, Fechtner RD, Cioffi GA, Coleman AL, Girkin CA, Liebmann JM, Singh K, Wilson MR, Wilson R, Kannel WB 2004; 138 (3): 458-467
  • Applying an Evidence-based Approach to the Management of Patients With Ocular Hypertension: Evaluating and Synthesizing Published Evidence American Journal of Ophthalmology Coleman AL, Singh K, Wilson R, Cioffi GA, Friedman DS, Weinreb RN 2004; 138 (S): 3-10
  • The Randomized Clinical Trial: Beware of Limitations Journal of Glaucoma Singh K 2004; 13 (2): 87-89
  • Dense pigmentation of the posterior lens capsule associated with the pigment dispersion syndrome JOURNAL OF GLAUCOMA Lin, D. Y., Volpicelli, M., Singh, K. 2003; 12 (6): 491-493

    Abstract

    To report an unusual case of pigment dispersion syndrome associated with unilateral dense pigmentation of the posterior lens capsule.Case report.A 59-year-old male with bilateral pigment dispersion syndrome presented with progressive decrease in visual acuity in the left eye over the past 10 to 20 years. Clinical examination revealed the typical findings of pigment dispersion syndrome including the presence of bilateral Krunkenberg spindles, iris transillumination defects, and heavy trabecular meshwork pigmentation. Of note, there was remarkably dense pigmentation of the posterior lens capsule in the eye with decreased visual acuity.Pigmentation of the posterior lens capsule may be a rare finding associated with pigment dispersion syndrome. Such a finding suggests that there may be aqueous flow into the retrolental space in some patients with this condition. The optimal treatment of this unusual condition remains undetermined.

    View details for Web of Science ID 000186877400009

    View details for PubMedID 14646685

  • Antibiotic resistance patterns of ocular bacterial flora - A prospective study of patients undergoing anterior segment surgery OPHTHALMOLOGY Ta, C. N., Chang, R. T., Singh, K., Egbert, P. R., Shriver, E. M., Blumenkranz, M. S., de Kaspar, H. M. 2003; 110 (10): 1946-1951

    Abstract

    To determine the antibiotic susceptibility patterns of conjunctival bacterial flora isolated preoperatively from patients undergoing anterior segment surgery.Prospective observational study.One hundred fifty-six eyes from 139 patients scheduled for anterior segment surgery were enrolled over a 6-month period from August 2001 to February 2002.Conjunctival cultures were obtained on the day of surgery before povidone-iodine or antibiotic application.Bacterial isolates were identified and tested for antibiotic susceptibility using the Kirby-Bauer disc-diffusion technique.Among the 156 eyes studied, 36 were from patients who had undergone either bilateral surgery or more than one surgery in the same eye. Only the first eyes of the 120 patients that underwent initial ocular surgery were included in our analysis. Of these 120 eyes, 21 (18%) showed no bacterial growth. Of the 143 bacterial strains isolated from the remaining 99 eyes, 112 (78%) were coagulase-negative staphylococci (CNS). Among the CNS, greater than 90% were susceptible to cefotaxime, levofloxacin, imipenem, meropenem, vancomycin, and each of the aminoglycosides except neomycin. Between 70% and 90% of the CNS were susceptible to cefazolin, neomycin, ciprofloxacin, ofloxacin, norfloxacin, and chloramphenicol. Less than 70% of the isolated CNS were sensitive to the penicillin analogues, ceftazidime, erythromycin, and tetracycline.Preoperative conjunctival isolates of CNS seem to be most sensitive to vancomycin, the aminoglycosides (except neomycin), and levofloxacin.

    View details for DOI 10.1016/S0161-6420(03)00735-8

    View details for Web of Science ID 000185615400015

    View details for PubMedID 14522770

  • Risk factors for antibiotic-resistant conjunctival bacterial flora in patients undergoing intraocular surgery GRAEFES ARCHIVE FOR CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY de Kaspar, H. M., Shriver, E. M., Nguyen, E. V., Egbert, P. R., Singh, K., Blumenkranz, M. S., Ta, C. N. 2003; 241 (9): 730-733

    Abstract

    The purpose of this study was to determine if patients with certain risk factors are more likely to harbor conjunctival bacterial flora resistant to multiple antibiotics.In this prospective study, detailed medical history and slit-lamp examination were performed on all patients prior to intraocular surgery. Patients with local risk factors were defined as those with chronic blepharitis, conjunctivitis or discharge. Those with systemic risk factors were patients with diabetes, autoimmune, immunodeficient or skin disorders, asthma and those taking immunosuppressant medications. Conjunctival cultures were obtained prior to preoperative antibiotics and povidone-iodine. Bacteria isolated were identified and antibiotic susceptibility was determined. Bacteria resistant to five or more antibiotics were defined as multi-resistant (MR).Among the 207 patients enrolled in the study, 73 patients had local risk factors. Of these patients, 32 patients (44%) carried MR organisms, compared to 32 of the 134 patients (24%) without local risk factors (P=0.0049). Thirty-two of 71 patients (45%) with systemic risk factors harbored MR organisms, compared to 32 of 136 patients (24%) without systemic risk factors (P=0.0025). Seventeen of 93 patients (18%) who had neither local nor systemic risk factors had MR organisms on their conjunctiva. In contrast, 17 of the 30 patients (57%) with both local and systemic risk factors (57%) carried MR bacteria (P=0.0001).Patients with local and/or systemic risk factors are more likely to harbor MR organisms. This may be one mechanism for the reported increased risk of postoperative endophthalmitis in this group of patients.

    View details for DOI 10.1007/s00417-003-0742-5

    View details for Web of Science ID 000186037100008

    View details for PubMedID 12928904

  • Prospective randomized comparison of 3-day versus 1-hour preoperative ofloxacin prophylaxis for cataract surgery OPHTHALMOLOGY Ta, C. N., Egbert, P. R., Singh, K., Shriver, E. M., Blumenkranz, M. S., de Kaspar, H. M. 2002; 109 (11): 2036-2040

    Abstract

    To determine the efficacy of reducing conjunctival bacterial flora with topical ofloxacin when given for 3 days compared with 1 hour before surgery.Prospective, randomized, controlled trial.Ninety-two eyes from 89 patients were randomized to a control group (48 eyes) or study group (44 eyes).All patients from both groups received topical ofloxacin 0.3% 1 hour before surgery and a 5% povidone iodine scrub of the periorbital area before surgery. The patients in the study group received additional ofloxacin four times daily for 3 days before surgery.Conjunctival cultures were obtained at five separate time points and were inoculated in solid and liquid culture media. The presence of bacteria was determined, quantified, and identified.Forty-two percent of eyes in the control group had positive conjunctival culture immediately before surgery, compared with 19% of eyes in the study group (P < 0.05). Immediately after surgery, 34% and 14% of eyes had positive cultures in the control and study groups, respectively (P < 0.05). Quantitatively, fewer bacteria were isolated from eyes in the study group compared with those in the control group for culture samples that were obtained both before povidone iodine scrub and at the conclusion of surgery (P

    View details for Web of Science ID 000178778600032

    View details for PubMedID 12414411

  • Combined Baerveldt glaucoma drainage implant and trabeculectomy with mitomycin C for refractory glaucoma JOURNAL OF GLAUCOMA Budenz, D. L., Scott, I. U., Nguyen, Q. H., Feuer, W., Singh, K., Nicolela, M. T., Bueche, M., Palmberg, P. F. 2002; 11 (5): 439-445

    Abstract

    To describe the surgical technique and clinical outcomes of a procedure for refractory glaucoma, concurrent Baerveldt glaucoma implant (BGI) and trabeculectomy with mitomycin C.Medical records of all patients who underwent combined Prolene-ligated BGI and trabeculectomy with mitomycin C were retrospectively reviewed. Main outcome measures were intraocular pressure (IOP), number of glaucoma medications, visual acuity, and complications. Kaplan-Meier survival analysis was used to determine success, defined as IOP < 22 mm Hg, no reoperation for glaucoma, and no loss of light perception vision.The mean +/- SD follow-up period for 38 eyes of 36 patients was 34 +/- 36 months (range, 3-121 months), during which 18 of 38 eyes (47%) required laser suture lysis of the Prolene suture. Intraocular pressure was reduced from a mean (+/- SD) preoperative value of 35.7 +/- 12.8 to 12.7 +/- 4.7 mm Hg at 1-year follow-up and 11.9 +/- 5.5 mm Hg at the last follow-up visit ( < 0.001). Number of medicines used for glaucoma was reduced from a mean +/- SD preoperative value of 2.5 +/- 0.9 to 0.5 +/- 0.6 at 1-year follow-up and 0.6 +/- 0.8 at the last follow-up visit ( < 0.001). LogMar visual acuity remained stable at mean of 1.15 +/- 0.85 preoperatively, compared with 1.14 +/- 1.05 at 1-year follow-up, but declined to 1.61 +/- 1.01 at the last follow-up visit, a loss of an average of four lines of vision ( = 0.004). Cumulative success was 91% at year 1, 86% at year 2, and 81% at year 3. Three eyes (8%) had suprachoroidal hemorrhages, one eye (3%) needed reoperation for an extruded implant, one (3%) eye had poor vision due to chronic hypotony, three eyes (8%) required additional glaucoma surgery during the postoperative period, and one eye (3%) needed revision of the implant for pressure control.Combined BGI and mitomycin C trabeculectomy provides excellent postoperative IOP control in patients with refractory glaucoma.

    View details for DOI 10.1097/01.IJG.0000029922.68321.88

    View details for Web of Science ID 000178511800013

    View details for PubMedID 12362086

  • Progression to end-stage glaucoma after laser in situ keratomileusis JOURNAL OF CATARACT AND REFRACTIVE SURGERY Shaikh, N. M., Shaikh, S., Singh, K., Manche, E. 2002; 28 (2): 356-359

    Abstract

    We describe 2 patients, one a glaucoma suspect because of family history and the other with juvenile glaucoma. Both patients developed complications after laser in situ keratomileusis that required frequent topical steroids, leading to steroid-induced glaucoma. In both cases, corneal edema from the acute rise in intraocular pressure (IOP) caused inaccurate IOP measurement by standard methods. The inability to recognize glaucoma early may have resulted in significant irreversible vision loss.

    View details for Web of Science ID 000173662600033

    View details for PubMedID 11821221

  • Emerging Perspectives in Glaucoma: Optimizing 24-hour Control of Intraocular Pressure American Journal of Ophthalmology Wax MB, Camras CB, Fiscella RG, Girkin C, Singh K, Weinreb RN 2002; 133 (S): 1-10
  • Setons and Serum IgG Titers to Silicone Journal of Glaucoma Shaikh S, Goldblum RS, Morse LS, Aslam R, Singh K 2002; 11 (6): 508-510
  • Combined Baerveldt Glaucoma Drainage Implant and Trabeculectomy with Mitomycin C for Refractory Glaucoma Journal of Glaucoma Budenz, D., Scott IU, Nguyen QH, Feuer W, Singh K, Nicolela MT, Bueche M, Palmberg PF 2002; 11 (5): 439-445
  • Combination Mitomycin C and 5-Fluorouracil Adjunctive to High Risk Trabeculectomy Tropical Ophthalmology Singh, K., Lin SA, Kim S 2002; 2 (3): 14-20
  • Automated Perimetry Ophthalmology Delgado MF, Nguyen NTA, Cox TA, Singh K, Lee DA, Dueker DK, Fechtner RD, Juzych, MS, Lin SC, Netland PA, Pastor SA, Schuman JS, Samples JR 2002; 109 (12): 2362-2374
  • Maximal Medical Therapy for Glaucoma. Know When to Say When Minerva Oftalmogica Singh, K., Fechtner RD 2002; 44: 1-4
  • Glaucoma care in West Africa JOURNAL OF GLAUCOMA Budenz, D. L., Singh, K. 2001; 10 (4): 348-353

    Abstract

    The authors draw on the peer review literature and 8 years of personal experience to provide an overview of the prevalence and management of glaucoma in West Africa.

    View details for Web of Science ID 000170658500016

    View details for PubMedID 11558821

  • Cyclophotocoagulation: A Report by the American Academy of Ophthalmology Ophthalmology Paster SA, Singh K, Lee DA, Juzych MS, Lin SC, Netland PA, Nguyen NT 2001; 108 (11): 2130-2138
  • Non-penetrating Glaucoma Surgery Ophthalmology Netland P, Lee DA, Juzych MS, Nguyen TA, Pastor SA, Robin AL, Singh K 2001; 108 (2): 416-421
  • Glaucoma Care in West Africa Journal of Glaucoma Budenz D, Singh K 2001; 10 (4): 348-353
  • Maximal Glaucoma Therapy Journal of Glaucoma Fechtner RD, Singh K 2001; 10 (5): 73-75
  • Trabeculectomy with intraoperative mitomycin C versus 5-fluorouracil - Prospective randomized clinical trial OPHTHALMOLOGY Singh, K., Mehta, K., Shaikh, N. M., Tsai, J. C., Moster, M. R., Budenz, D. L., Greenfield, D. S., Chen, P. P., Cohen, J. S., Baerveldt, G. S., Shaikh, S. 2000; 107 (12): 2305-2309

    Abstract

    To evaluate the relative efficacy and safety of 5-fluorouracil (5-FU) and mitomycin C (MMC) when used as adjuncts with primary trabeculectomy in eyes not at high risk for failure.Prospective multicenter, randomized clinical trial.One hundred thirteen patients with primary open-angle, pseudoexfoliative, pigmentary, or angle-closure glaucoma undergoing primary trabeculectomy were recruited.One eye of each patient was randomized to receive either 5-FU (50 mg/ml for 5 minutes) or MMC (0.4 mg/ml for 2 minutes).Intraocular pressure (IOP), visual acuity, complications, and interventions were documented at fixed intervals after surgery. The study also examined progression of visual field loss, long-term complications, and bleb appearance 3 years after surgery.Of the 108 patients with complete perioperative information, 54 eyes received 5-FU and 54 received MMC. The proportion of patients reaching different predefined target IOPs after surgery was slightly higher in the MMC group than in the 5-FU group. This difference was less than 25%, which would have been necessary to achieve statistical significance with a power of 0.8 and the sample size used. Likewise, there was no statistically significant difference between the groups with regard to mean preoperative IOP, complications, or interventions. Mean postoperative follow-up was 309 and 330 days in the 5-FU and MMC groups, respectively (P = 0.593).5-Fluorouracil and MMC were found to be equally safe and effective adjuncts to primary trabeculectomy in the short- and medium-term postoperative periods.

    View details for Web of Science ID 000165586900057

    View details for PubMedID 11097613

  • Randomized Clinical Trial of Trabeculectomy with Intraoperative Mitomycin C versus 5-Fluorouracil Journal of the Organization of the Panhellenic Ophthalmological Society Singh, K. 2000; 12 (3): 244-249
  • Target IOP: Glaucoma's Holey Grail Ophthalmology Singh K, Spaeth G, Zimmerman T, Minckler D 2000; 107 (4): 629-630
  • Migration Patterns and Practice Choices of Newly Trained Ophthalmologists Internet Journal of Ophthalmology Gable MS, Mohr JD, Singh K 2000; 5: 01-06
  • Emerging Perspective on Glaucoma American Journal of Ophthalmology Lee DA, Fechtner RD, Fiscella RG, Singh K, Stewart WC 2000; 130 (4): S1-11
  • The subspecialty training, practice type, and geographical distribution of recently trained ophthalmologists: a study of male and female physicians. Journal of the American Medical Women's Association (1972) Gable, M. S., MOHR, J. D., O'Brien, T. P., Lee, P., Colenbrander, A., Singh, K. 2000; 55 (1): 20-?

    Abstract

    To characterize the distribution of male and female ophthalmologists with regard to practice type, subspecialty training, rural-urban distribution, and regional distribution.Ophthalmology Matching Program files containing the records of residents who began their second year at accredited programs between 1986 and 1990 (inclusive), were compared to membership files of the American Academy of Ophthalmology. Practice locations for each individual were classified according to region, stage, and Rural-Urban Continuum County Code, as defined by the US Department of Agriculture.This cohort comprised 2,494 individuals, 77.1% (1922) of whom were male and 22.9% (572) of whom were female. Group practice was most common (55.9% for women and 61.3% for men). More women were in salaried positions associated with health maintenance organizations (p = 0.006) and academic settings (p < 0.001) than were men. Notable differences in subspecialty choice were restricted to pediatric ophthalmology, chosen three times more frequently by women, and vitreoretinal diseases/surgery, chosen twice as often by men. Only 5.6% of women selected nonmetropolitan practice locales compared to approximately twice that percentage of men. The Middle Atlantic and New England regions attracted more women, while the South Atlantic attracted more men.

    View details for PubMedID 10680402

  • Effects of Carteolol and Timolol on Plasma Lipid Profiles in Older Women with Ocular Hypertension or Primary Open-Angle Glaucoma American Journal of Ophthalmology Stewart WC, Dubiner HB, Mundorf TK, Laibovitz RA, Sall KN, Katz LJ, Singh K. Shulman DG, Siegel LI, Hudgins AC, Nussbaum L, Apostolaros M 1999; 127 (2): 142-147
  • Comparison of Phacotrabeculectomy with 5-Fluorouracil, Mitomycin C, and Without Antifibrotic Agents Ophthalmic Surgery and Lasers Budenz D, Pyfer M, Singh K, Gordon J, Piltz-Seymour J, Keates EU 1999; 30 (5): 367-374
  • Medical control of intraocular pressure after cataract surgery JOURNAL OF CATARACT AND REFRACTIVE SURGERY Byrd, S., Singh, K. 1998; 24 (11): 1493-1497

    Abstract

    To compare the effectiveness of 2 medications commonly used to prevent intraocular pressure (IOP) elevation in the early period after cataract surgery.Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA.This prospective study comprised 202 eyes of patients scheduled for cataract extraction who agreed to participate. Patients were randomized to receive oral acetazolamide, 500 mg 1 hour preoperatively; oral acetazolamide, 500 mg immediately postoperatively; apraclonidine hydrochloride 1%, 2 drops 1 hour preoperatively; or artificial tears (control group). Intraocular pressure was measured preoperatively and 4 to 6 and 24 hours postoperatively.Preoperative IOP was not significantly different among the 4 groups. At 4 to 6 hours postoperatively, only preoperative acetazolamide was significantly more effective than the control medication (P = .038); at 24 hours there were no significant differences among the 4 groups. Postoperative IOP elevation in excess of 35 mm Hg at 6 or 24 hours decreased significantly in the preoperative acetazolamide group (3/46 eyes) compared with the control group (14/54 eyes). There was no statistically significant difference in IOP elevation between eyes having extracapsular cataract extraction and those having phacoemulsification, independent of treatment group.The results favor preoperative acetazolamide to control postcataract IOP elevation. The method of cataract removal did not affect postoperative IOP elevation.

    View details for Web of Science ID 000076836300024

    View details for PubMedID 9818340

  • Delayed corneal epitheliopathy after antimetabolite-augmented trabeculectomy JOURNAL OF GLAUCOMA Manche, E. E., Afshari, M. A., Singh, K. 1998; 7 (4): 237-239

    Abstract

    The authors describe the first case of delayed antimetabolite-related corneal epithelial toxicity after trabeculectomy and its successful treatment with limbal stem cell transplantation.A 73-year-old woman underwent trabeculectomy with intraoperative mitomycin C. After surgery she received six 5-mg injections of subconjunctival 5-fluorouracil (5-FU) adjacent to the bleb.The patient had a functioning trabeculectomy and clear cornea until 30 months after surgery, at which time she developed a nonhealing superior corneal epithelial defect. After 4 months of conservative medical management, an autologous limbal stem cell transplantation was performed. The epithelial defect resolved completely within 1 week of limbal stem cell transplantation.Delayed corneal epithelial toxicity may be a late complication of antimetabolite-augmented trabeculectomy.

    View details for Web of Science ID 000075303500004

    View details for PubMedID 9713780

  • Risk of hypotony after primary trabeculectomy with antifibrotic agents in a black West African population JOURNAL OF GLAUCOMA Singh, K., Byrd, S., Egbert, P. R., Budenz, D. 1998; 7 (2): 82-85

    Abstract

    To evaluate the risk of hypotony and hypotony maculopathy following trabeculectomy with 5-fluorouracil (5-FU) and mitomycin C (MMC) in a black West African population.One hundred and one eyes of black Ghanaian patients with advanced primary open-angle glaucoma received intraoperative antifibrotic therapy with trabeculectomy as part of two randomized clinical trials. Overall, 57 patients received 5-FU (50.0 mg/ml for 5 minutes) and 44 received MMC (0.5 mg/ml for 3.5 minutes). All cases were performed by one of five surgeons at a single outpatient surgery center.Two of 101 eyes had a final intraocular pressure (IOP) of less than 5 mm Hg and were thus classified as having hypotony. No patient in either group was noted to develop hypotony-related maculopathy. Overall mean pre- and postoperative IOPs were 30.1 and 15.9 mm Hg, respectively. The patients receiving intraoperative MMC had a lower mean postoperative IOP (14.7 mm Hg) than those receiving 5-FU (first study, 17.1 mm Hg; second study, 16.7 mm Hg; p = 0.05). Mean overall follow-up was 17.7 months and did not differ significantly between the MMC and combined 5-FU groups.Hypotony following trabeculectomy supplemented with antifibrotic agents is a rare complication in this population. No eyes in either clinical trial developed hypotony maculopathy, suggesting that the prevalence of this condition is substantially lower in black West Africans than in whites.

    View details for Web of Science ID 000072804500003

    View details for PubMedID 9559492

  • Antimetabolite Application: Science or Voodoo Journal of Glaucoma Singh K 1997; 6 (5): 271-273
  • Trabeculectomy with intraoperative 5-fluorouracil vs mitomycin C AMERICAN JOURNAL OF OPHTHALMOLOGY Singh, K., Egbert, P. R., Byrd, S., Budenz, D. L., Williams, A. S., Decker, J. H., Dadzie, P. 1997; 123 (1): 48-53

    Abstract

    To compare the effectiveness of intraoperative 5-fluorouracil (5-FU) and mitomycin C used adjunctively with trabeculectomy in a black West African population.Eighty-five consecutive eyes of 85 black patients undergoing primary trabeculectomy for open-angle glaucoma were prospectively randomly assigned to receive either 5-FU (50 mg/ml for 5 minutes) or mitomycin C (0.5 mg/ml for 3 1/2 minutes) intraoperatively by soaked sponge.Of the 81 eyes with at least a 3-month postoperative follow-up, 41 of 44 (93.2%) in the mitomycin C group and 27 of 37 (73.0%) in the 5-FU group had a final intraocular pressure of less than 21 mm Hg (P = .01). Twenty-eight of 44 eyes (63.6%) in the mitomycin C group and 18 of 37 (51.4%) in the 5-FU group had a final intraocular pressure of less than 15 mm Hg (P = .26). Mean postoperative intraocular pressure was 13.7 mm Hg in the mitomycin C group and 16.3 mm Hg in the 5-FU group (P = .05). There were no differences between the two groups in mean age, preoperative intraocular pressure, postoperative visual acuity, and complications. Mean follow-up was 10.0 +/- 4.41 months (range, 4 to 19 months).The adjunctive use of mitomycin C with trabeculectomy is equally safe and more efficacious compared to 5-FU in this West African population. Use of mitomycin C in this study was not associated with a statistically significantly greater proportion of patients achieving low intraocular pressure (less than 15 mm Hg) compared to 5-FU.

    View details for Web of Science ID A1997WB82200006

    View details for PubMedID 9186096

  • Clinical Pharmacology and Use of Dorzolamide (Trusopt): A Topical Ocular Carbonic Anhydrase Inhibitor in the Treatment of Glaucoma Today's Therapeutic Trends Singh K, Zimmerman TJ 1996; 14 (2): 3
  • Update on the Status of Topical Beta-Blockers in the Treatment of Glaucoma Ophthalmology Clinics of North America Singh K, Zimmerman TJ 1995; 8 (2): 295-302
  • A PROSPECTIVE TRIAL OF INTRAOPERATIVE FLUOROURACIL DURING TRABECULECTOMY IN A BLACK-POPULATION AMERICAN JOURNAL OF OPHTHALMOLOGY Egbert, P. R., Williams, A. S., Singh, K., Dadzie, P., Egbert, T. B. 1993; 116 (5): 612-616

    Abstract

    In a study population of black Africans with advanced glaucoma in Ghana we conducted a prospective study of intraoperative 5-fluorouracil alone. Eyes undergoing trabeculectomy were randomly selected either to receive or not receive a single intraoperative application of 5-fluorouracil (50 mg/ml for five minutes). Fifty-five eyes had a mean follow-up of 282 days (minimum, 92 days). Twenty of 24 eyes (83%) in the 5-fluorouracil group vs 12 of 31 eyes (39%) in the control group had postoperative intraocular pressure of 20 mm Hg or less with or without medical therapy (P = .01). Eleven of 24 eyes (46%) in the 5-fluorouracil group and five of 31 eyes (16%) in the control group had intraocular pressure of 15 mm Hg or less (P = .02). Without medical therapy, 17 of 24 eyes (71%) in the 5-fluorouracil group and ten of 31 eyes (32%) in the control group had intraocular pressure of 20 mm Hg or less (P = .02). The overall complications were similar in the two groups. In this population, intraoperative 5-fluorouracil markedly improved the ability of trabeculectomy to lower intraocular pressure. We recommend that intraoperative 5-fluorouracil be considered in glaucoma surgery with poor prognosis as an alternative to postoperative subconjunctival injections when multiple injections are not feasible.

    View details for Web of Science ID A1993MF62400011

    View details for PubMedID 8238222

  • Glaucoma: A global problem. Seminars in Opthalmology Singh K 1993; 8 (3): 190-195
  • Acute Idiopathic Blind Spot Enlargement: A Spectrum of Disease Ophthalmology Singh K, DeFrank MP, Watzke RC, Shults WT 1991; 98 (4): 497-502
  • A Population-Based Evaluation of Glaucoma Screening: The Baltimore Eye Survey American Journal of Epidemiology Tielsch JM, Sommer A, Katz J. Quigley HA, Gottsch JD, Javitt J, Singh K, the Baltimore Eye Survey Research Group 1991; 134 (10): 1102-1110
  • Socioeconomic Status and Visual Impairment Among Urban Americans Archives of Ophthalmology Tielsch JM, Sommer A, Katz J, Quigley H, Ezrine S, the Baltimore Eye Survey Research Group: (Sommer A, Tielsch JM, Quigley H, Gottsch J, Royall R, Katz J, Witt K, Singh K, Javitt J, Ezrine S 1991; 109 (5): 637-641
  • Relationship Between Intraocular Pressure and Primary Open Angle Glaucoma Among White and Black Americans: The Baltimore Eye Survey Archives of Ophthalmology Sommer A, Tielsch JM, Katz J, Quigley HA, Gottsch JD, Javitt J, Singh K, the Baltimore Eye Survey Research Group 1991; 109 (8): 1090-1095
  • Blindness and Visual Impairment in an American Urban Population: The Baltimore Eye Survey Archives of Ophthalmology Tielsch JM, Sommer A, Witt K, Katz J, Royall RM, The Baltimore Eye Survey Research Group: (Sommer A, Tielsch JM, Quigley H, Gottsch J, Royall R, Katz J, Witt K, Singh K 1990; 108 (2): 286-290
  • Intraocular Lens Power Calculations: A Practical Evaluation in Normal Subjects at the Wilmer Institute Archives of Ophthalmology Singh K, Sommer A, Jensen AD, Payne JW 1987; 105 (8): 1046-1050

Conference Proceedings


  • Nonprogressive glaucomatous cupping and visual field abnormalities in young Chinese males Kreidl, K. O., Lombardi, L., Singh, K. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2004: U678-U678
  • A prospective comparison of patient preference with two topical timolol preparations Haw, W., Byrd, S., Singh, K., Tran, T. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2004: U677-U677
  • Comparison of preoperative conjunctival bacterial flora in patients undergoing glaucoma or cataract surgery Kreidl, K. O., Singh, K., de Kaspar, H. M., Ta, C. N. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2003: U369-U369
  • Ten-fold reduction of conjunctival bacterial contamination rate using a combined 3-day application of topical ofloxacin and iodine irrigation in patients undergoing anterior segment intraocular surgery de Kaspar, H. M., Singh, G., Egbert, P. R., Haw, W. W., Nguyen, E. V., Singh, K., Blumenkranz, M. S., Ta, C. N. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2003: U344-U344
  • Bacterial contamination of paracentesis blades used in cataract surgery Chang, R. T., Ta, C. N., Egbert, P. R., Singh, K., Haw, W. W., Shriver, E. M., Espinosa, L., Williams, D. Y., Blumenkranz, M. S., de Kaspar, H. M. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2002: U73-U73
  • Multiresistant Staphylococcus epidermidis on the conjunctiva prior to intraocular surgery Shriver, E. M., Ta, C. N., Egbert, P. R., Singh, K., Chang, R. T., Blumenkranz, M. S., de Kaspar, H. M. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2002: U860-U860
  • Antibiotic susceptibility pattern of coagulase-negative staphylococci in patients undergoing Intraocular surgery Ta, C. N., de Kaspar, H. M., Chang, R. T., Shriver, E. M., Egbert, P. R., Singh, K., Blumenkranz, M. S. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2002: U1275-U1275
  • Antibiotic susceptibility pattern of coagulase-negative staphylococci in patients undergoing intraocular surgery. Ta, C. N., de Kaspar, H., Egbert, P., Singh, K., Blumenkranz, M. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2001: S254-S254
  • Immediate bacterial contamination of the aqueous humor in intraocular surgery. Braun, M., de Kaspar, H., Ta, C. N., Egbert, P., Singh, K., Blumenkranz, M. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2001: S256-S256
  • Inhibition of Tenon's fibroblast proliferation and collagen synthesis by clarithromycin, colchicine, verapamil and captopril Singh, K., Byrd, S. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 1997: 1234-1234
  • The effect of transient hypotony on final visual acuity following combined trabeculectomy with cataract surgery Ta, C., Byrd, S., Singh, K. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 1997: 1210-1210
  • Risk of hypotony following antimetabolite trabeculectomy in a black West African Singh, K., Egbert, P. R., Budenz, D., Dadzie, P. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 1996: 1161-1161
  • COMBINED SETON IMPLANTATION AND MITOMYCIN TRABECULECTOMY Singh, K., Bueche, M., Budenz, D., Palmberg, P. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 1993: 731-731

Stanford Medicine Resources: