Bio

Bio


Dr. Chang is a clinician-scientist with a busy surgical practice and an interest in early stage medical device development and healthcare IT startups. His clinical research revolves around understanding the association between myopia and glaucoma. He is currently co-developing EyeGo for Remote Eye Care Triage.

Clinical Focus


  • Mobile Health
  • Entrepreneurship
  • Narrow-Angle Glaucoma
  • Glaucoma, Suspect
  • Vision Screening
  • Myopia
  • Ophthalmology
  • Visual Field Tests
  • Glaucoma Drainage Implants
  • Glaucoma and cataract surgery
  • Optical Coherence Tomography
  • Medical Education

Academic Appointments


Administrative Appointments


  • Glaucoma Fellowship Co-Director, Stanford Ophthalmology (2009 - Present)

Honors & Awards


  • Heed Fellow, Heed Foundation (2007)

Boards, Advisory Committees, Professional Organizations


  • Fellow, AAO (2009 - Present)
  • Member, AGS (2009 - Present)

Professional Education


  • Residency:Washington University in St Louis (2007) MO
  • Fellowship:Bascom Palmer Eye Institute (2009) FL
  • Internship:Northshore University Health System (2004) IL
  • Medical Education:University of Missouri (2002) MO
  • Board Certification: Ophthalmology, American Board of Ophthalmology (2008)

Community and International Work


  • Lifeline Express Volunteer Educator, Lanzhou, Mianyang, Nanjing, Urumqi, Zhengzhou, Jilin, etc.

    Topic

    cataract and glaucoma lecturer

    Partnering Organization(s)

    China Lifeline Express Foundation

    Populations Served

    rural China

    Location

    International

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    No

Research & Scholarship

Current Research and Scholarly Interests


I am a clinician-scientist (80% clinical 20% research) focusing on patient care, physician innovation, biodesign, and design thinking.

Startup Projects:
1) EyeGo -- custom iPhone attachment coupled with a HIPAA-secure app to facilitate taking pictures of the front and the back of the eye to enhance physician to physician communication
2) Eyeguru.org -- free online interactive education platform using spaced repetition to help teach the subjective interpretation of optic disc photos
3) Keepyoursight.org -- nonprofit foundation developing free online visual field screening

Selected Current and Past Research Projects:
1) Young Chinese Myopes with Minimally Progressive Field Defects
2) Determining Optic Nerve Head Anatomical Correlates in Chinese and Caucasian Myopes With and Without Visual Field Defects Using SD OCT
3) Examining the Differences in Corneal Biomechanical Properties in Patients with Glaucoma and Myopia Using the Oculus Corvis ST
4) Effectiveness of Low Vision Referrals: An Assessment of Patient Quality of Life and Physician Perceptions of Low Vision Services at Aravind Eye Hospital
5) Employing Gaze-Tracking Analysis to Determine How Subjects Gather Visual Information During Field Testing
6) Predictive Factors for Performance on Visual Field Testing in Patients with Glaucomatous Disease
7) Comparison of SD-OCT Structural Parameters in Chinese Patients with Normal-Tension Glaucoma and Primary Open Angle Glaucoma
8) Peristat Online Visual Field Screening for Glaucoma
9) Dietary, Supplemental and Total Intake of Select Nutrients with Risk of Glaucoma in the Women’s Health Initiative (WHI)
10) Factors Associated with Patient Satisfaction Scores for Cataract and Glaucoma Patients
11) Remote Triage by Ophthalmic Imaging with Mobile Devices
12) Rarebit Perimetry Normative Database Collection and Test Parameter Analysis
13) Cirrus SD OCT –Ganglion Cell Normative Database Collection

Clinical Trials


  • Comparing Safety and Efficacy of BOL-303259-X With Timolol Maleate in Subjects With Open-Angle Glaucoma or Ocular Hypertension Recruiting

    In participants with a diagnosis of open angle glaucoma (OAG) or ocular hypertension (OHT), the primary objective is to demonstrate that the mean IOP reduction after 3 months of treatment with BOL-303259-X once daily (QD) is non-inferior to timolol maleate 0.5% twice daily (BID). The secondary objective is to demonstrate the superiority of BOL-303259-X QD to timolol maleate 0.5% BID. This assessment will be performed if the non-inferiority of BOL-303259-X QD to timolol maleate 0.5% BID is determined. An open label safety phase will be conducted at the end of Visit 6 (3 months) where all participants will receive BOL-303259-X QD for an additional 9 months.

    View full details

  • The Secondary Beneficial Effects of Prostaglandin Analog Treatment in Thyroid Eye Disease Patients. Not Recruiting

    The purpose of this study is to evaluate the potential secondary beneficial effect of prostaglandin analogues (PA) treatment in thyroid eye disease (TED) patients. This study aims to determine if PA would change the course of the orbitopathy in TED patients by altering the progression of the common features of TED, including fatty hypertrophy, proptosis, eyelid retraction and optic nerve compression. The eyes with thyroid eye disease and elevated intraocular pressure will be randomised to the PA treatment and the other eye will serve as a control eye and will be treated with Timolol.

    Stanford is currently not accepting patients for this trial. For more information, please contact Barbara Bartlett, 650-724-9259.

    View full details

Teaching

2013-14 Courses


Publications

Journal Articles


  • 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

  • Fundus Photography Still a Valuable Tool in Glaucoma Care Ophthalmology Times Chang, R. 2013; 38 (8)
  • 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

  • Glaucoma Diagnostic Accuracy of Ganglion Cell-Inner Plexiform Layer Thickness: Comparison with Nerve Fiber Layer and Optic Nerve Head OPHTHALMOLOGY Mwanza, J., Durbin, M. K., Budenz, D. L., Sayyad, F. E., Chang, R. T., Neelakantan, A., Godfrey, D. G., Carter, R., Crandall, A. S. 2012; 119 (6): 1151-1158

    Abstract

    To determine the diagnostic performance of macular ganglion cell-inner plexiform layer (GCIPL) thickness measured with the Cirrus high-definition optical coherence tomography (HD-OCT) ganglion cell analysis (GCA) algorithm (Carl Zeiss Meditec, Dublin, CA) to discriminate normal eyes and eyes with early glaucoma and to compare it with that of peripapillary retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) measurements.Evaluation of diagnostic test or technology.Fifty-eight patients with early glaucoma and 99 age-matched normal subjects.Macular GCIPL and peripapillary RNFL thicknesses and ONH parameters were measured in each participant, and their diagnostic abilities were compared.Area under the curve (AUC) of the receiver operating characteristic.The GCIPL parameters with the best AUCs were the minimum (0.959), inferotemporal (0.956), average (0.935), superotemporal (0.919), and inferior sector (0.918). There were no significant differences between these AUCs and those of inferior quadrant (0.939), average (0.936), and superior quadrant RNFL (0.933); vertical cup-to-disc diameter ratio (0.962); cup-to-disc area ratio (0.933); and rim area (0.910), all P>0.05.The ability of macular GCIPL parameters to discriminate normal eyes and eyes with early glaucoma is high and comparable to that of the best peripapillary RNFL and ONH parameters.Proprietary or commercial disclosure may be found after the references.

    View details for DOI 10.1016/j.ophtha.2011.12.014

    View details for Web of Science ID 000304717100010

    View details for PubMedID 22365056

  • Risk Factors for Visual Field Progression View on Glaucoma Chang RT, Singh K 2012; 7 (1): 18-22
  • Cyclodialysis Cleft Glaucoma Today Chang RT 2012; May/June: 40
  • High Myopia Poses Challenges Ophthalmology Times Chang RT 2012; 37 (12)
  • Macular Ganglion Cell-Inner Plexiform Layer: Automated Detection and Thickness Reproducibility with Spectral Domain-Optical Coherence Tomography in Glaucoma INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Mwanza, J., Oakley, J. D., Budenz, D. L., Chang, R. T., Knight, O. J., Feuer, W. J. 2011; 52 (11): 8323-8329

    Abstract

    To demonstrate the capability of SD-OCT to measure macular retinal ganglion cell-inner plexiform layer (GCIPL) thickness and to assess its reproducibility in glaucomatous eyes.Fifty-one glaucomatous eyes (26 mild, 11 moderate, 14 severe) of 51 patients underwent macular scanning using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) macula 200×200 acquisition protocol. Five scans were obtained on 5 days within 2 months. The ganglion cell analysis (GCA) algorithm was used to detect the macular GCIPL and to measure the thickness of the overall average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL. The reproducibility of the measurements was evaluated with intraclass correlation coefficients (ICCs), coefficients of variation (COVs), and test-retest standard deviations (TRTSDs).Segmentation and measurement of GCIPL thickness were successful in 50 of 51 subjects. All ICCs ranged between 0.94 and 0.98, but ICCs for average and superior GCIPL parameters (0.97-0.98) were slightly higher than for inferior GCIPL parameters (0.94-0.97). All COVs were <5%, with 1.8% for average GCIPL and COVs for superior GCIPL parameters (2.2%-3.0%) slightly lower than those for inferior GCIPL parameters (2.5%-3.6%). The TRTSD was lowest for average GCIPL (1.16 ?m) and varied from 1.43 to 2.15 ?m for sectoral GCIPL CONCLUSIONS: The Cirrus HD-OCT GCA algorithm can successfully segment macular GCIPL and measure GCIPL thickness with excellent intervisit reproducibility. Longitudinal monitoring of GCIPL thickness may be possible with Cirrus HD-OCT for assessing glaucoma progression.

    View details for DOI 10.1167/iovs.11-7962

    View details for Web of Science ID 000296907700012

    View details for PubMedID 21917932

  • Myopia and glaucoma. International ophthalmology clinics Chang, R. T. 2011; 51 (3): 53-63

    View details for DOI 10.1097/IIO.0b013e31821e5342

    View details for PubMedID 21633238

  • Reproducibility of Peripapillary Retinal Nerve Fiber Layer Thickness and Optic Nerve Head Parameters Measured with Cirrus HD-OCT in Glaucomatous Eyes INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Mwanza, J., Chang, R. T., Budenz, D. L., Durbin, M. K., Gendy, M. G., Shi, W., Feuer, W. J. 2010; 51 (11): 5724-5730

    Abstract

    To assess the reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) parameters measured with Cirrus HD-OCT in glaucomatous eyes.Fifty-five glaucomatous eyes were included in the study. The optic disc cube 200 × 200 protocol was used to obtain three scans during the same visit to evaluate the intravisit reproducibility. One scan on 4 additional days within a 2-month period of the first session was obtained to assess intervisit reproducibility. Intraclass correlation coefficient (ICC), coefficient of variation (CV), and test-retest SD (TRT SD) were calculated for each RNFL and ONH parameter. The formula 1.645 × ?2 × intervisit TRT SD provides an upper tolerance limit to variability beyond which nonphysiologic change should be considered.All ICCs were excellent, ranging from 83.9% to 99.2% for intravisit measurements and from 80.8% to 99.1% for intervisit measurements. Cup/disc area ratio had the lowest CV (1.1%) in either type of measurement, followed by average RNFL thickness (1.9% and 2.7%). Nasal clock hours and quadrants showed the poorest reproducibility as did the clock hour directly temporally. The intervisit tolerance limit for average RNFL thickness was 3.89 ?m.Intravisit and intervisit measurements of peripapillary RNFL thickness and ONH parameters with Cirrus HD-OCT showed excellent reproducibility, indicating that this instrument may be useful in monitoring glaucoma progression. When comparing two measurements from the same eye on two different visits, a reproducible decrease in average RNFL thickness of approximately 4 ?m or more may be considered a statistically significant change from baseline.

    View details for DOI 10.1167/iovs.10-5222

    View details for Web of Science ID 000283558400041

    View details for PubMedID 20574014

  • The Utility of the Monocular Trial Data from the Ocular Hypertension Treatment Study OPHTHALMOLOGY Bhorade, A. M., Wilson, B. S., Gordon, M. O., Palmberg, P., Weinreb, R. N., Miller, E., Chang, R. T., Kass, M. A. 2010; 117 (11): 2047-2054

    Abstract

    To determine whether adjusting the intraocular pressure (IOP) change of the trial eye for the IOP change of the fellow eye (i.e., monocular trial) is a better assessment of medication response than testing each eye independently.Analysis of data from a prospective, randomized, clinical trial.Two hundred six participants with ocular hypertension randomized to the observation group and later started on a topical prostaglandin analog (PGA).Participants were started on a topical PGA in 1 eye and returned in approximately 1 month to determine medication response. The IOP response of the trial eye was determined by the IOP change between baseline and 1 month in the trial eye alone (unadjusted method) and by adjusting for the IOP change in the fellow eye between the same visits (adjusted method). Our "gold standard" for medication response was the IOP change in the trial eye between up to 3 pre- and 3 posttreatment visits on the same medication. Pearson correlation was used to compare the gold standard with the unadjusted and adjusted methods. In addition, symmetry of IOP response between trial and fellow eyes to the same medication was determined by correlating the trial eye IOP change between up to 3 pre- and 3 posttreatment visits to the fellow eye IOP change between the same visits.Correlations of IOP change of the trial eye using the gold standard to the IOP change of the trial eye using the unadjusted and adjusted methods.The correlations of IOP change using the gold standard to the IOP change using the unadjusted and adjusted methods were r = 0.40 and r = 0.41, respectively. The correlation of IOP change of both eyes between the same pre- and posttreatment visits was r = 0.81.The monocular trial (i.e., adjusted method) appears equivalent to testing each eye independently (i.e., unadjusted method); however, neither method is adequate to determine medication response to topical PGAs. Both eyes have a similar IOP response to the same PGA. Further studies to understand IOP fluctuation are necessary to improve current methods of assessing medication response.Proprietary or commercial disclosure may be found after the references.

    View details for DOI 10.1016/j.ophtha.2010.02.020

    View details for Web of Science ID 000283264200002

    View details for PubMedID 20619460

  • Sensitivity and Specificity of Time-Domain versus Spectral-Domain Optical Coherence Tomography in Diagnosing Early to Moderate Glaucoma OPHTHALMOLOGY Chang, R. T., Knight, O. J., Feuer, W. J., Budenz, D. L. 2009; 116 (12): 2294-2299

    Abstract

    To evaluate the sensitivity and specificity of measurements of retinal nerve fiber layer (RNFL) thickness in early to moderate glaucoma using Stratus time-domain and Cirrus spectral-domain optical coherence tomography (OCT; Carl Zeiss Meditec, Dublin, CA).Evaluation of diagnostic test or technology.Fifty-four glaucoma subjects with early to moderate visual field defects and 50 age-matched normal subjects.Three peripapillary RNFL scans of 1 eye of each subject using Stratus and Cirrus OCT.Sensitivity and specificity of average, quadrant, and clock-hour RNFL thickness.The average age+/-standard deviation in the normal and glaucoma groups was 62.9+/-12.7 years (range, 40-84 years) and 67.6+/-11.4 (range, 42-85 years), respectively (P = 0.05). The glaucoma group consisted of 34 early (average mean deviation, -3.20+/-1.22 dB) and 20 moderate (average mean deviation, -8.05+/-1.87 dB) glaucomas. Cirrus OCT sensitivity and specificity for average RNFL abnormal at the 5% level were 83% and 88%, respectively, and at the 1% level were 65% and 100%, respectively. Stratus OCT sensitivity and specificity for average RNFL abnormal at the 5% level were 80% and 94%, respectively, and at the 1% level were 61% and 100%, respectively. For 1 or more abnormal quadrants at the 5% level, the sensitivity and specificity for Cirrus OCT were 98% and 80%, respectively, and at the 1% level were 87% and 92%, respectively. For 1 or more quadrants abnormal at the 5% level, the sensitivity and specificity for Stratus OCT were 96% and 76%, respectively, and at the 1% level were 74% and 94%, respectively. Cirrus OCT sensitivity and specificity using a criterion of 1 or more abnormal clock hours at the 5% level were 100% and 72%, respectively, and at the 1% level were 85% and 94%, respectively. Stratus OCT sensitivity and specificity for 1 or more abnormal clock hours at the 5% level were 98% and 66%, respectively, and at the 1% level were 85% and 90%, respectively.The sensitivity and specificity of various RNFL parameters using the Cirrus OCT for glaucoma with early to moderate visual field defects are excellent and are equivalent to Stratus OCT.

    View details for DOI 10.1016/j.ophtha.2009.06.012

    View details for Web of Science ID 000272579200005

    View details for PubMedID 19800694

  • Comparison of Retinal Nerve Fiber Layer Measurements Using Time Domain and Spectral Domain Optical Coherent Tomography OPHTHALMOLOGY Knight, O. J., Chang, R. T., Feuer, W. J., Budenz, D. L. 2009; 116 (7): 1271-1277

    Abstract

    To determine the agreement between peripapillary retinal nerve fiber layer (RNFL) thickness measurements from Stratus time domain optical coherence tomography (OCT) and Cirrus spectral domain OCT (Carl Zeiss Meditec, Dublin, CA) in normal subjects and subjects with glaucoma.Evaluation of diagnostic test or technology.A total of 130 eyes from 130 normal subjects and subjects with glaucoma were analyzed. The subjects were divided into groups by visual field criteria: normal (n = 29), glaucoma suspect (n = 12), mild glaucoma (n = 41), moderate glaucoma (n = 18), and severe glaucoma (n = 30).Peripapillary RNFL thickness was measured with Stratus Fast RNFL and Cirrus 200 x 200 Optic Disc Scan on the same day in 1 eye of each subject to determine agreement. Two operators used the same instruments for all scans.Student paired t testing, Pearson's correlation coefficient, and Bland-Altman analysis of RNFL thickness measurements.The average age of the glaucoma group was significantly more than that of the normal group: 68.3+/-12.3 years versus 55.7+/-12.1 years, respectively. For Stratus OCT, the average RNFL thickness (mean +/- standard deviation) was 99.4+/-13.2 microm, 94.5+/-15.0 microm, 79.0+/-14.5 microm, 62.7+/-10.2 microm, and 51.0+/-8.9 microm for the normal, suspect, mild, moderate, and severe groups, respectively. For Cirrus OCT, the corresponding measurements were 92.0+/-10.8 microm, 88.1+/-13.5 microm, 73.3+/-11.8 microm, 60.9+/-8.3 microm, and 55.3+/-6.6 microm. All Stratus-Cirrus differences were statistically significant by paired t testing (P<0.001) except for the moderate group (P = 0.11). For average RNFL, there was also a highly significant linear relationship between Stratus minus Cirrus difference and RNFL thickness (P<0.001). Bland-Altman plots showed that the systematic difference of Stratus measurements are smaller than Cirrus at thinner RNFL values but larger at thicker RNFL values.RNFL thickness measurements between Stratus OCT and Cirrus OCT cannot be directly compared. Clinicians should be aware that measurements are generally higher with Stratus than with Cirrus except when the RNFL is very thin, as in severe glaucoma. This difference must be taken into account if comparing Stratus measurements with Cirrus measurements.

    View details for DOI 10.1016/j.ophtha.2008.12.032

    View details for Web of Science ID 000267789900007

    View details for PubMedID 19395086

  • Diagnosing glaucoma progression. International ophthalmology clinics Chang, R. T., Budenz, D. L. 2008; 48 (4): 13-28

    View details for DOI 10.1097/IIO.0b013e31818b63f0

    View details for PubMedID 18936634

  • Calibration of fundus images using spectral domain optical coherence tomography OPHTHALMIC SURGERY LASERS & IMAGING Lujan, B. J., Wang, F., Gregori, G., Rosenfeld, P. J., Knighton, R. W., Puliafito, C. A., Danis, R. P., Hubbard, L. D., Chang, R. T., Budenz, D. L., Seider, M. I., Knight, O. 2008; 39 (4): S15-S20

    Abstract

    Measurements performed on fundus images using current software are not accurate. Accurate measurements can be obtained only by calibrating a fundus camera using measurements between fixed retinal landmarks, such as the dimensions of the optic nerve, or by relying on a calibrated model eye provided by a reading center. However, calibrated spectral domain OCT (SD-OCT) could offer a convenient alternative method for the calibration of any fundus image.The ability to measure exact distances on SD-OCT fundus images was tested by measuring the distance between the center of the fovea and the optic nerve. Calibrated SD-OCT scans measuring 6 X 6 X 2 mm centered on the fovea and the optic nerve were analyzed in 50 healthy right eyes. The foveal center was identified using cross-sectional SD-OCT images, and the center of the optic nerve was identified manually. The SD-OCT scans were registered to each other, and the distances between the center of the optic nerve and fovea were calculated. The overlay of these SD-OCT fundus images on photographic fundus images was performed.Any image of the fundus could be calibrated by overlaying the SD-OCT fundus image, and the measurements were consistent with previously defined calibration methods. The mean distance between the center of the fovea and the center of the optic nerve was 4.32 +/-0.32 mm. The line from the center of the optic nerve to the foveal center had a mean declination of 7.67 +/- 3.88 degrees. Mean horizontal displacement and vertical displacement were 4.27 +/- 0.29 mm and 0.58 +/- 0.29 mm, respectively.The overlay of the SD-OCT fundus image provides a convenient method for calibrating any image of the fundus. This approach should provide a uniform standard when comparing images from different devices and from different reading centers.

    View details for Web of Science ID 000258283000003

    View details for PubMedID 18777875

  • New developments in optical coherence tomography for glaucoma CURRENT OPINION IN OPHTHALMOLOGY Chang, R., Budenz, D. L. 2008; 19 (2): 127-135

    Abstract

    Structural imaging is becoming a powerful adjunct for the diagnosis and progression of glaucoma. There are several competing technologies in this arena. Optical coherence tomography continues to evolve at a fast pace, so it can be challenging to keep up with the latest information. This review covers the recent papers relevant to optical coherence tomography for glaucoma.Retinal nerve fiber layer imaging by optical coherence tomography is reliable. Age, ethnicity, axial length and optic disc size can affect the machine's normative range. Scan quality can be affected by movement, media opacities, myopia and severity of disease. The sensitivity and specificity are variable across multiple studies. Despite this, the technology is beginning to help us understand the structure-function relationship in glaucoma.The next generation optical coherence tomography is around the corner. By understanding the current strengths and limitations of this advancing technology, one can better assess its use in clinical practice.

    View details for Web of Science ID 000253545800008

    View details for PubMedID 18301286

  • Reproducibility of retinal nerve fiber thickness measurements using the stratus OCT in normal and glaucomatous eyes INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Budenz, D. L., Chang, R. T., Huang, X. R., Knighton, R. W., Tielsch, J. M. 2005; 46 (7): 2440-2443

    Abstract

    To determine the reproducibility of Stratus Optical Coherence Tomography (OCT) retinal nerve fiber layer (RNFL) measurements around the optic nerve in normal and glaucomatous eyes.One eye was chosen at random from 88 normal subjects and 59 glaucomatous subjects distributed among mild, moderate, and severe glaucoma, determined by visual field testing. Subjects underwent six RNFL thickness measurements performed by a single operator over a 30-minute period with a brief rest between sessions. Three scans were taken with the high-density Standard RNFL protocol, and three were taken with the Fast RNFL protocol, alternating between scan protocols.Reliability, as measured by intraclass correlation coefficient (ICC), was calculated for the overall mean RNFL thickness and for each quadrant. The ICC for the mean Standard RNFL thickness (and lower 95% confidence interval [CI]) in normal and glaucomatous eyes was 0.97 (0.96 CI) and 0.98 (0.97 CI), respectively. The ICC for the mean Fast RNFL thickness in normal and glaucomatous eyes was 0.95 (0.93 CI) and 0.97 (0.95 CI), respectively. Quadrant ICCs ranged between 0.79 and 0.97, with the nasal quadrant being the least reproducible of all four quadrants, using either the Standard or Fast RNFL program. The test-retest variability ranged from 3.5 microm for the average RNFL thickness measurements in normal eyes to 13.8 microm for the nasal quadrant measurements in glaucomatous eyes, which appeared to be the most variable.Reproducibility of RNFL measurements using the Stratus OCT is excellent in normal and glaucomatous eyes. The nasal quadrant appears to be the most variable measurement. Standard RNFL and Fast RNFL scans are equally reproducible and yield comparable measurements. These findings have implications for the diagnosis of glaucoma and glaucomatous progression.

    View details for DOI 10.1167/iovs.04-1174

    View details for Web of Science ID 000230112800029

    View details for PubMedID 15980233

  • 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

  • Sensitivity and specificity of the StratusOCT for perimetric glaucoma OPHTHALMOLOGY Budenz, D. L., Michael, A., Chang, R. T., McSoley, J., Katz, J. 2005; 112 (1): 3-9

    Abstract

    To determine the sensitivity and specificity of measurements of the retinal nerve fiber layer (RNFL) using the StratusOCT in glaucoma subjects with visual field (VF) defects.Prospective cross-sectional study.One hundred nine normal and 63 glaucoma subjects.Fast RNFL scans were performed in one eye of each patient using the StratusOCT.Sensitivity and specificity of different optical coherence tomography (OCT) criteria for identifying glaucoma subjects with glaucomatous VF defects.Areas under the receiver operating characteristic curves (AROCs) for various OCT parameters.Severity of VF defects in the glaucoma group was distributed between mild (18 subjects), moderate (21 subjects), and severe (24 subjects). The average mean deviation of the glaucoma fields was -8.4 decibels (dB), with a standard deviation of 6.0 dB and a range from -0.14 to -28.0 dB. The sensitivity and specificity using a criterion of average RNFL thickness abnormal at the <5% level were 84% and 98%, respectively. The sensitivity and specificity using a criterion of average RNFL thickness abnormal at the <1% level were 68% and 100%. The sensitivity and specificity of using a criterion of >or=1 quadrants abnormal at the <5% level were 89% and 95%. The sensitivity and specificity of using a criterion of >or=1 quadrants abnormal at the <1% level were 83% and 100%. The sensitivity and specificity of using a criterion of >or=1 clock hours abnormal at the <5% level were 89% and 92%. The sensitivity and specificity of using a criterion of >or=1 quadrants abnormal at the <1% level were 83% and 100%. The AROC for mean RNFL thickness was 0.966. Other high AROC values included the superior quadrant (0.952), inferior quadrant (0.971), inferotemporal clock hour at 7-o'clock (right eye) and 5-o'clock (left eye) (0.959), 6-o'clock hour (0.940), superotemporal clock hour at 11-o'clock (right eye) and 1-o'clock (left eye) (0.935), and 12-o'clock hour (0.924).The sensitivity and specificity of RNFL measurements using the new StratusOCT for glaucoma with manifest VF defects are excellent. The best parameters seem to be >or=1 quadrants abnormal at the or=1 clock hours abnormal at the

    View details for DOI 10.1016/j.ophtha.2004.06.039

    View details for Web of Science ID 000226242800002

    View details for PubMedID 15629813

  • 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

  • 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

Conference Proceedings


  • 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
  • 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
  • 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

Presentations


  • Smartphone and Gadgets

    Time Period

    3/6/2014

    Presented To

    NANOS

    Location

    Puerto Rico

  • Smartphone Adapters for Ocular Image Capture

    Time Period

    2/8/2014

    Presented To

    Glaucoma 360

    Location

    San Francisco

  • 6 Lessons Using SD-OCT

    Time Period

    12/27/2013

    Presented To

    Glaucoma Update Thailand

    Location

    bangkok

  • Visual Field Defects in High Myopes

    Time Period

    11/11/2013

    Presented To

    ISO

    Location

    Guangzhou

  • Glaucoma: Early Diagnosis and Prevention of Blindness

    Time Period

    8/10/2013

    Presented To

    Pan American Ophthalmology Congress

    Location

    Rio de Janeiro

  • Genetics of Glaucoma

    Stanford Basic Science Course

    Time Period

    7/24/2013

    Presented To

    Stanford

    Location

    palo alto

  • Glaucoma and Myopia: Challenges and Pearls for Progression Detection

    Time Period

    7/19/2013

    Presented To

    World Glaucoma Congress

    Location

    Vancouver

  • Update in Ophthalmology

    CME Lecture

    Time Period

    7/12/2013

    Presented To

    Dominican Hospital

    Location

    Santa Cruz

  • Fixing the Plumbing of the Eye

    Time Period

    4/27/2013

    Presented To

    ASORN

    Location

    palo alto

  • The Art of Fundus Photo Interpretation

    Glaucoma 360 Meeting

    Time Period

    2/2/2013

    Presented To

    Glaucoma Research Foundation

    Location

    San Francisco

  • IPhone Physician Education and Reference Tools

    Time Period

    11/11/2012

    Presented To

    American Academic of Ophthalmology

    Location

    Chicago

  • OCT Diagnostic Performance Studies

    Workshop

    Time Period

    10/5/2012

    Presented To

    FDA

    Location

    washington dc

  • Collagen Disease and Glaucoma

    Time Period

    4/16/2012

    Presented To

    Asia Pacific Academy of Ophthalmology

    Location

    Busan

  • Myopia and Glaucoma

    Time Period

    2/3/2012

    Presented To

    Glaucoma 360

    Location

    San Francisco

  • Iphone Apps and the Present/Future of Patient Education

    Time Period

    11/1/2011

    Presented To

    Grand Rounds Stanford

    Location

    Stanford

  • Management of Acute Angle Closure

    Time Period

    3/21/2011

    Presented To

    Asia Pacific Academy of Ophthalmology

    Location

    Sydney

  • Trabeculectomy Failure

    Time Period

    7/2/2011

    Presented To

    World Glaucoma Congress

    Location

    Paris

  • Glaucoma Technology: Surgical Innovation

    Time Period

    1/29/2011

    Presented To

    Stanford Biodesign

    Location

    Palo Alto

  • Glaucoma Devices: Diagnostic and Therapeutic

    Time Period

    8/26/2010

    Presented To

    Stanford Biodesign

    Location

    Palo Alto

  • Retcam Goniography

    Time Period

    3/3/2010

    Presented To

    AGS PreSurgical Meeting

    Location

    Naples,FL

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