COMPLICATIONS WITH THE ROUTE FOR DRUG DELIVERY

that the risk of infectious endophthalmitis following intravitreal injection is small. The exact rate of endophthalmitis after intravitreal injection is unknown due to the paucity of large reported series. The highest reported rate to date is 0.9% for TA and 0.01% for bevacizumab.

The role of topical antibiotics to prevent postoperative endophthalmitis remains controversial. Topical antibiotics may be applied after the injection for a few days, as the break in the conjunctiva and sclera is not completely healed and water-sealed. In addition there may be a synergistic effect between topical antibiotics and povidone-iodine. However, no studies have demonstrated that reducing the conjunctival bacterial count also results in a lower risk for endophthalmitis. Given the paucity of data regarding intraocular infections, there is no evidence supporting the use of antibiotics after intravitreal injections. In fact, there has never been a prospective randomized study showing the benefit of topical antibiotics in preventing endophthalmitis. Such a study would require thousands of patients covering all aspects of the procedure. However, a study of this magnitude is not feasible. There is general agreement

A survey on published studies and case series, including more than 15000 intravitreal injections in 4400 eyes, determined a prevalence of endophthalmitis (including pseudo-endophthalmitis) after TA injections of 0.3% per injection and 0.9% per eye. The overall prevalence for retinal detachments was 3.9% per eye or 0.9% per injection. The prevalence of intraocular inflammation (iritis, uveitis, vitritis, and/or ante- rior-chamber inflammation) was 28.5% per eye and 6.3% (839/13 400) per injection. Traumatic cataracts (Figure 10.5), intraocular hemorrhage (i.e., retinal hemorrhage, vitreous hemorrhage, or hyphema) were occasionally reported after intravitreal injection. Temporary hypotony, defined as an intraocular pressure of <4 mmHg, may occur rarely after intravitreal injections and is primarily limited to eyes receiving antiviral therapy. Some cases of retinal artery occlusion have also been reported after intravitreal injections.