Topical Antibiotics Not Necessary for Intravitreal Injections

Caroline Helwick

November 11, 2012

CHICAGO — Topical antibiotic prophylaxis is completely unnecessary in association with intravitreal injections, according to findings from more than 15,000 injections by a single surgeon who presented his data here at the American Academy of Ophthalmology (AAO) 2012 Annual Meeting.

"Only 1 patient out of more than 15,000 developed endophthalmitis in the absence of prophylaxis," said Abdhish R. Bhavsar, MD, attending surgeon and retina-vitreous specialist at the Phillips Eye Institute in Minneapolis, Minnesota.

Topical antibiotics are used frequently in clinical practice in association with intravitreous injections, although level 1 evidence for this practice does not exist, Dr. Bhavsar said.

Recent surveys by the American Society of Retina Specialists have suggested that 40% of retina specialists use topical antibiotics prior to administration of anti–vascular endothelial growth factor (VEGF) intravitreal injections, and 86% use topical antibiotics after the procedure, he said.

Because strong supportive evidence is lacking and because randomized controlled trials of this practice are not feasible, Dr. Bhavsar and colleagues evaluated their own consecutive series of 15,023 intravitreous injections done without topical antibiotic prophylaxis, either before or after the injections.

The 3269 patients (mean age, 79 years) were treated primarily for age-related macular degeneration. Less common indications included diabetic macular edema and cystoid macular edema due to retinal vein occlusion and other diseases. The injections included bevacizumab (12,099), ranibizumab (1481), triamcinolone acetonide (993), pegaptanib sodium (370), dexamethasone implant (63), ganciclovir (10), and triesence (7).

All injections were given with topical proparacaine and tetracaine, topical povidone iodine conjunctival prep (pre- and postinjection), a sterile eyelid speculum, and clean, nonsterile gloves.

Only 1 case of endophthalmitis was observed. "The patient who developed endophthalmitis had worn an extended-wear contact lens immediately after the intravitreous injection, which may have contributed [to the infection]," he noted.

There were 7 cases of retinal detachment. Secondary uveitis developed in 50 eyes, steroid responder glaucoma occurred in 74 eyes after triamcinolone acetonide injection, and secondary glaucoma developed in 1 eye after bevacizumab injection.

Povidone Iodine Is Sufficient

"No study has proven that any medication reduces the risk of endophthalmitis after intravitreous injections. Povidone iodine is the only substance proven to reduce the risk after intraocular surgery," Dr. Bhavsar said.

Having trained at the University of California–Los Angeles Jules Stein Eye Institute, where the original studies on povidone iodine were conducted, Dr. Bhavsar said he became a believer that this agent is effective alone in preventing infection, and he has never used topical antibiotics.

His own practice is to place at least 1 drop of povidone iodine 5% on the ocular surface of the eye after injection to eliminate any viable bacteria that may have been expressed onto the ocular surface or injection site during the removal of the speculum. This has been shown to be effective at minimizing the number of bacterial colony-forming units and species for the first postoperative day compared with broad-spectrum antibiotics, he said.

In addition, the antimicrobial effect of a drop of povidone iodine 5% has been shown to last at least 24 hours after intraocular surgery, which has not similarly been shown for antibiotics, he added.

Although the evidence for a lack of preventive efficacy is not from a randomized trial, Dr. Bhavsar believes it should be convincing enough to alter this unnecessary practice, he told Medscape Medical News.

Susan B. Bressler, MD, professor of ophthalmology at the Wilmer Eye Institute at Johns Hopkins University, Baltimore, Maryland, agreed with the findings and conclusion.

"There is no scientific evidence that preprocedural or postprocedural antibiotics affect the rate of endophthalmitis," she said. "When we started our Diabetic Retinopathy Clinical Research Network 10 years ago, many practitioners were using pre- or postantibiotic prophylaxis, even though the Network did not require it. After 10 years of experience, the majority use neither at this point. Physicians have become increasingly comfortable acting on the clinical evidence — which is that there is no clinical evidence of its utility."

Dr. Bressler suggested that when ophthalmologists continue to use antibiotics for intravitreal injections, they do so because they believe it protects them from litigation in the very unlikely case of an infection. The publication of data such as these is important in correcting the perception that the lack of prophylaxis is a clinical and medicolegal risk, she said.

Dr. Bhavsar and Dr. Bressler have disclosed no relevant financial relationships.

American Academy of Ophthalmology (AAO) 2012 Annual Meeting: Abstract PO232. Presented November 10, 2012.