To determine the roles of immediate pars plana vitrectomy (VIT) and systemic antibiotic treatment in the management of postoperative endophthalmitis.

Investigator-initiated, multicenter, randomized clinical trial.

Private and university-based retina-vitreous practices.

A total of 420 patients who had clinical evidence of endophthalmitis within 6 weeks after cataract surgery or secondary intraocular lens implantation.

Random assignment according to a 2 x 2 factorial design to treatment with VIT or vitreous tap or biopsy (TAP) and to treatment with or without systemic antibiotics (ceftazidime and amikacin).

A 9-month evaluation of visual acuity assessed by an Early Treatment Diabetic Retinopathy Study acuity chart and media clarity assessed both clinically and photographically.

There was no difference in final visual acuity or media clarity with or without the use of systemic antibiotics. In patients whose initial visual acuity was hand motions or better, there was no difference in visual outcome whether or not an immediate VIT was performed. However, in the subgroup of patients with initial light perception-only vision, VIT produced a threefold increase in the frequency of achieving 20/40 or better acuity (33% vs 11%), approximately a twofold chance of achieving 20/100 or better acuity (56% vs 30%), and a 50% decrease in the frequency of severe visual loss (20% vs 47%) over TAP. In this group of patients, the difference between VIT and TAP was statistically significant (P < .001, log rank test for cumulative visual acuity scores) over the entire range of vision.

Omission of systemic antibiotic treatment can reduce toxic effects, costs, and length of hospital stay. Routine immediate VIT is not necessary in patients with better than light perception vision at presentation but is of substantial benefit for those who have light perception-only vision.