Purpose: To assess the incidence rate of endophthalmitis after 25-gauge pars plana vitrectomy and to compare it with the endophthalmitis rate after 20-gauge pars plana vitrectomy.
Design: Retrospective, interventional, comparative cohort study.
Participants: Eight thousand six hundred one consecutive pars plana vitrectomy surgery patients.
Methods: Surgeries performed at a single institution between January 1, 2004, and September 1, 2006, were reviewed.
Main outcome measures: Incidence of postvitrectomy endophthalmitis.
Results: Endophthalmitis developed in 1 of 5498 eyes after 20-gauge vitrectomy (0.018%) and in 7 of 3103 eyes after 25-gauge vitrectomy cases (0.23%; P = 0.004). Median final visual acuity was counting fingers or hand movements (range, 20/50-no light perception), with comparable results between 20-gauge and 25-gauge endophthalmitis cases.
Conclusions: The visual outcomes of vitrectomy-associated endophthalmitis, for both 20-gauge and 25-gauge vitrectomy, is poor. In this study population, 25-gauge vitrectomy had a statistically significant 12-fold higher incidence of endophthalmitis compared with 20-gauge vitrectomy.