Topical 0.5% moxifloxacin prevents endophthalmitis in an intravitreal injection rabbit model.

INTRODUCTION

Intravitreal injections for the treatment of retinal disease have increased the risk of endophthalmitis. We developed a rabbit model to investigate whether topical 0.5% moxifloxacin could prevent endophthalmitis after an intravitreal injection.

METHODS

A rabbit model of intravitreal injection to produce endophthalmitis was developed by injecting triamcinolone into the vitreous through a depot of subconjunctival Staphylococcus aureus (10(7) cfu). Endophthalmitis was evaluated clinically and confirmed by culture. The model was tested with a commercially available brand of topical 0.5% moxifloxacin (N = 10) and saline (N = 10). In brief, after bacterial subconjunctival challenge, a topical treatment was administered every 15 min for 1 h. Immediately thereafter, triamcinolone was injected into the vitreous through the treated bacterial depot. Topical 0.5% moxifloxacin and saline were administered QID over the next 72 h. All rabbits were examined daily, euthanized, and tested for viable bacteria when clinical signs of endophthalmitis were observed.

RESULTS

Anti-infective treatment with topical 0.5% moxifloxacin prevented the development of endophthalmitis (0/9 rabbits), compared to topical saline (6/10 rabbits; P = 0.01; power = 0.99).

CONCLUSIONS

Topical 0.5% moxifloxacin provided effective prophylaxis to prevent endophthalmitis after an intravitreal injection of triamcinolone. This unique model may prove valuable to demonstrate prophylaxis for other anti-infectives at an intravitreal injection site.