Aim To compare early versus delayed intravitreal betamethasone as an adjuvant in the treatment of presumed acute postoperative endophthalmitis after phacoemulsification.

Methods Patients with presumed postcataract surgery endophthalmitis were included in this prospective, randomised, multicentre study. On admission, patients received intravitreal vancomycin and ceftazidime, and were randomly assigned to intravitreal betamethasone injection (early-IVB) group or no immediate injection (delayed-IVB) group. After 48 h, a second intravitreal antibiotic injection associated with intravitreal betamethasone was given to all patients. In patients with severe endophthalmitis or clinical deterioration, a prompt or delayed vitrectomy was performed. The primary outcome was the proportion of patients achieving a visual acuity (VA) of 20/40 or better at 12 months. The secondary outcomes were the rate of delayed vitrectomy and the rate of complications (retinal detachment and phthisis).

Results Ninety-seven eyes of 97 patients were included, 45 in the early-IVB group and 52 in the delayed-IVB group. Overall, 62.9% of patients achieved a VA ≥20/40 at 1 year. There was no statistically significant difference in the visual outcome between the two groups at 1 year, whatever their baseline VA or light perception or hand motion or more (p=0.55 and p=0.10, respectively). The rates of delayed vitrectomy, retinal detachment and phthisis bulbi were not significantly different between the two groups (p=0.42, p=0.37 and p=0.44, respectively).

Conclusions Early intravitreal betamethasone had no clear advantage versus delayed injection in the management of presumed postoperative endophthalmitis.