Comparison of a Single Intraopereative Sub-Tenon’s Capsule Delivery of Antibiotic in Controlled-Release System versus Conventional Postoperative Eye Drops in Preventing Endophthalmitis in a Rabbit Model

Abstract

Purpose:: To compare the potential of one sub-Tenon’s capsule injection of 2 mg-ciprofloxacin in a biodegradable controlled-release system (Duocat) with the common practice of dosing conventional 0.3% ciprofloxacin eye drops 6 times a day for infection prophylaxis after cataract surgery in a rabbit model of endophthalmitis.

Methods:: In this in vivo laboratory investigation two regimens of ciprofloxacin delivery were tested for prophylaxis to prevent endophthalmitis: (A) 0.3% ciprofloxacin eye drops every 4 hours (a total of 6 drops); (B) a single sub-Tenon’s capsule injection of 2mg-Duocat following an anterior chamber injection of 0.0025 ml of saline containing 5 x 10⁷ colony-forming units of a clinical isolate of Staphylococcus epidermidis (ciprofloxacin-sensitive). A saline control was tested concurrently in all three experiments. At 24 hours after injection, the eyes were evaluated by slit lamp in a masked fashion for clinical signs of endophthalmitis, and the anterior and posterior chambers were cultured for bacteria.

Results:: The median clinical scores for both ciprofloxacin treated groups were significantly lower than the saline group. The median clinical score for the Duocat group was significantly lower than the conventional ciprofloxacin eye drops. The anterior and chambers were negative for S. epidermidis in all two treatment regimens.

Conclusions:: The findings from our study neither advocate nor support the prophylactic use of antibiotics in cataract surgery, but do imply that both routes may be equally tolerated, with short-term performance clearly favoring the Duocat system over eye drops for all the clinical aspects of improvement tested in this investigation. Duocat may provide greater anti-infective protection in cataract surgery and merits further evaluation.

Keywords: antibiotics/antifungals/antiparasitics • drug toxicity/drug effects • cataract