Prophylaxis of endophthalmitis

Prophylactic antibiotics can be administered by various routes to prevent endophthalmitis. Topical application is simple and minimally invasive, but it provides relatively poor penetration into the vitreous. Collagen shields are effective in delivering therapeutic levels of antibiotics to the cornea and aqueous but not to the vitreous cavity. Systemic administration for prophylaxis is questionable because of the poor ocular penetration of most drugs (however, some antibiotics, such as imipenem, pefloxacin, and ciprofloxacin, may provide therapeutic levels to the vitreous). Subconjunctival injection may provide significant drug levels in the aqueous for 4 to 6 hours. However, we found subconjunctival gentamicin ineffective in experimentally induced Pseudomonas aeruginosa endophthalmitis in postoperative aphakic eyes. We recommend the use of antibiotics in infusion fluid. In cases of trauma, we inject 48 micrograms gentamicin and 54 micrograms clindamycin intracamerally or intravitreally.