Prophylactic Topical Antibiotics Did Not Decrease Rate of Endophthalmitis after Intravitreal Injection in Retrospective Study

The rate of endophthalmitis after more than 90,000 intravitreal injections was found to be approximately 1 in 3000 in a retrospective study of a consecutive series of cases at a multicenter, retina-only practice. Prophylactic use of topical antibiotics was not found to decrease this rate.

Intravitreal injection has become one of the most common medical procedures in the United States and is typically used to treat diabetic macular edema and neovascular age-related macular degeneration. Although this invasive procedure is generally well tolerated, endophthalmitis is a rare complication with potentially devastating consequences.

In the past, many physicians prescribed topical ophthalmic antibiotics to prevent endophthalmitis after intravitreal injection. However, large clinical trials have not supported this practice, and guidelines have stated that insufficient evidence exists to endorse it, so it has fallen out of favor.

To determine the incidence of endophthalmitis after intravitreal injection and to compare the rate of endophthalmitis when prophylactic topical antibiotics were routinely used with that after their use was discontinued, records of all patients seen by Retina Consultants of Houston from 2011 through 2014 were retrospectively reviewed. The aim of this review was to identify the total number of intravitreal injections given and all cases of clinically suspected endophthalmitis related to these injections. Results of this retrospective case review were published in a recent issue of Retina.

In 2011, during the initial phase of the study, topical ophthalmic antibiotics were typically prescribed for use from 1—3 days before to 1–3 days after intravitreal injection. However, in the first quarter of 2012, this practice was phased out. As a result, by 2013, most patients receiving intravitreal injection did not use prophylactic topical antibiotics.

During the study period, 90,339 intravitreal injections were given, and 30 cases of endophthalmitis were identified, which resulted in an endophthalmitis rate of 0.033%, or approximately 1 case in 3011 intravitreal injections.

The rate of endophthalmitis with topical antibiotic use was 0.035%, compared with a rate of 0.021% without such use (P = 0.261). As a result, the investigators concluded that topical antibiotics did not decrease the rate of endophthalmitis after intravitreal injection in this patient population.

Results of microbiological analysis revealed that the most common organisms isolated from patients with endophthalmitis were coagulase-negative staphylococci (in 10 cases, or 33%) and Streptococcus mitis (in 2 cases, or 7%). However, in 14 cases (47%), cultures produced negative results.