Surveillance for potential adverse events associated with the use of intravitreal bevacizumab for retinal and choroidal vascular disease
RETINA-THE JOURNAL OF RETINAL AND VITREOUS DISEASES
2008; 28 (8): 1151-1158
Bacterial contamination of ocular surface and needles in patients undergoing intravitreal injections
RETINA-THE JOURNAL OF RETINAL AND VITREOUS DISEASES
2008; 28 (6): 877-883
To systematically study potential adverse events associated with the use of intraocular bevacizumab at a single medical center.Retrospective study of all consecutive patients receiving intraocular bevacizumab injections at the Stanford University Department of Ophthalmology between November 15, 2005 and July 14, 2006. Bevacizumab was given for exudative age-related macular degeneration, retinal vascular occlusion, diabetic macular edema, neovascular glaucoma, and five other indications.We analyzed medical records of 186 subjects (203 eyes) who received a total of 578 injections of 1.25 mg of bevacizumab. The average follow-up was approximately 6 months. Five eyes with exudative age-related macular degeneration developed retinal pigment epithelial (RPE) tears, all with preexisting RPE detachments. These five eyes represented 2.9% of all age-related macular degeneration eyes treated and 7% of the age-related macular degeneration eyes with preexisting RPE detachments at initiation of treatment. Other adverse events were rare and included retinal ischemia, subretinal hemorrhage, vitreous hemorrhage, ocular irritation or pain, worsened hypertension, and headache. No death or thromboembolic events were observed.Intraocular bevacizumab appears to be well tolerated for the treatment of a variety of retinal and choroidal vascular diseases. RPE tears may occur when treating choroidal neovascularization, particularly in patients with preexisting RPE detachment.
View details for Web of Science ID 000259329100018
View details for PubMedID 18685542
Candida (amphotericin-sensitive) lens abscess associated with decreasing arterial blood flow in a very low birth weight preterm infant
2002; 110 (5)
To evaluate potential sources of bacterial contamination during intravitreal (IVT) injection procedures.Patients scheduled for IVT injection were asked to enroll in the study at the California Vitreoretinal Center (Menlo Park, CA) and the Vantage Eye Center (Salinas, CA) between October 2004 and April 2005. A total of 104 patients participated in the study, with a total of 118 IVT injection procedures performed on 107 eyes. Standard microbiological techniques were used to culture, identify, and quantify bacterial contamination of injection needles and the bulbar conjunctiva at the injection site in patients undergoing IVT injections. The main outcomes measured were type and quantity of bacterial isolates.Two (2%) of 114 needles collected were contaminated with bacteria. The prevalence of bacterial contamination of the injection site on the bulbar conjunctiva was 43% before prophylaxis on the day of the injection with topical antibiotics and povidone-iodine, with a statistically significant reduction to 13% after prophylaxis (P < 0.0001). Coagulase-negative Staphylococcus, the most common bacterium isolated from the ocular surface, was isolated from both culture-positive needles.IVT injection needles became contaminated with bacteria during the injection procedure. Although the contamination rate was low, this supports a mechanism of postinjection endophthalmitis in which there is direct inoculation of ocular surface flora into the vitreous cavity by the injection needle.
View details for Web of Science ID 000256714300014
View details for PubMedID 18536606
Effects of the pulsed electron avalanche knife on retinal tissue
ARCHIVES OF OPHTHALMOLOGY
2002; 120 (5): 636-640
In this report, we review the case of a candidal lens abscess in a premature infant girl who was 28 weeks' gestational age at birth. The culture obtained from the lens abscess grew Candida albicans sensitive to amphotericin B but resistant to flucytosine. This case is unique in that the infant developed a fungal lens cataract at 34 weeks' postconceptional age during the last week of a 30-day course of amphotericin B. The embryonic hyaloid artery system, which perfuses the developing lens, regresses between 29 and 32 weeks of gestation; thus, the mechanism for an infection of the lens may be inoculation of the lens by Candida before hyaloid artery system regression, followed by developmental loss of this blood supply, which makes the lens inaccessible to antimicrobial penetration. Candidal endophthalmitis with lens abscess is an uncommon morbidity that requires prompt recognition and surgical intervention for effective management.
View details for Web of Science ID 000178971800015
View details for PubMedID 12415071
Pulsed Electron Avalanche Knife (PEAK) for intraocular surgery
INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
2001; 42 (11): 2673-2678
To evaluate the precision of retinal tissue dissection by the pulsed electron avalanche knife (PEAK) and to assess possible toxic effects from this device.To demonstrate precision of cutting, bovine retina (in vitro) and rabbit retina (in vivo) were incised with the PEAK. Samples were examined by scanning electron microscopy and histologic examination (light microscopy). To evaluate possible toxic effects in rabbit eyes, 30 000 pulses were delivered into the vitreous 1 cm above the retina. Histologic examinations and electroretinography were performed at intervals up to 1 month after exposure.Cuts in postmortem bovine retina showed extremely sharp edges with no signs of thermal damage. Full-thickness cuts in living attached rabbit retina were similarly sharp and were typically less than 100 microm wide. No signs of retinal toxic effects were detected by histologic examination or electroretinography.The PEAK is capable of precise cutting through retinal tissue, and there are no demonstrable retinal toxic effects from its use. The precision and tractionless nature of PEAK cutting offers advantages over mechanical tools and laser-based instrumentation. We believe this new device will prove useful in a variety of vitreoretinal surgical applications.
View details for Web of Science ID 000175503400015
View details for PubMedID 12003616
To develop a better and more economical instrument for precise, tractionless, "cold" cutting during intraocular surgery. The use of highly localized electric fields rather than laser light as the means of tissue dissection was investigated.A high electric field at the tip of a fine wire can, like lasers, initiate plasma formation. Micrometer-length plasma streamers are generated when an insulated 25 micron (microm) wire, exposed to physiological medium at one end, is subjected to nanosecond electrical pulses between 1 and 8 kV in magnitude. The explosive evaporation of water in the vicinity of these streamers cuts soft tissue without heat deposition into surrounding material (cold cutting). Streamers of plasma and the dynamics of water evaporation were imaged using an inverted microscope and fast flash photography. Cutting effectiveness was evaluated on both polyacrylamide gels, on different tissues from excised bovine eyes, and in vivo on rabbit retina. Standard histology techniques were used to examine the tissue.Electric pulses with energies between 150 and 670 microJ produced plasma streamers in saline between 10 and 200 microm in length. Application of electric discharges to dense (10%) polyacrylamide gels resulted in fracturing of the gel without ejection of bulk material. In both dense and softer (6%) gels, layer by layer shaving was possible with pulse energy rather than number of pulses as the determinant of ultimate cutting depth. The instrument made precise partial or full-thickness cuts of retina, iris, lens, and lens capsule without any evidence of thermal damage. Because different tissues require distinct energies for dissection, tissue-selective cutting on complex structures can be performed if the appropriate pulse energies are used; for example, retina can be dissected without damage to the major retinal vessels.This instrument, called the Pulsed Electron Avalanche Knife (PEAK), can quickly and precisely cut intraocular tissues without traction. The small delivery probe and modest cost make it promising for many ophthalmic applications, including retinal, cataract, and glaucoma surgery. In addition, the instrument may be useful in nonophthalmic procedures such as intravascular surgery and neurosurgery.
View details for Web of Science ID 000171433300037
View details for PubMedID 11581215