LAUSR

PURPOSE To identify determinants of adverse outcomes in acute retinal necrosis (ARN), presenting characteristics and incidence rates of vision loss and ocular complications in a cohort of polymerase chain reaction (PCR)-positive eyes were analyzed. DESIGN Retrospective observational cohort study. METHODS Forty-one eyes of 36 patients with clinically diagnosed ARN, PCR-positive for herpes simplex virus or varicella zoster virus and evaluated between January 2002 and June 2013, were included. Main outcome measures included incidence rates of vision loss and retinal detachment (RD). RESULTS Presenting visual acuity was generally poor (20/50 to >20/200 in 27%; 20/200 or worse in 56%). The incidence rate of ≤20/200 was 0.66/eye-year (EY), (95% confidence interval [CI], 0.32/EY to 1.22/EY); the rate of light perception or no light perception vision was 0.07/EY (95% CI, 0.02/EY to 0.16/EY). During follow-up, 59% of eyes developed at least 1 RD (rate = 0.40/EY, 95% CI, 0.19/EY to 0.58/EY). Eyes with retinitis involving ≥25% of the retina at presentation detached at nearly 12 times the rate, as compared to those with <25% retinal involvement (0.70/EY vs 0.06/EY; P = .001). Development of an RD was the greatest determinant of adverse visual outcomes, with 4% of eyes, that had experienced at least 1 RD, achieving a best-corrected visual acuity of ≥20/40 compared to 53% of eyes that never detached (P = .0003). CONCLUSIONS Poor outcomes in ARN were common in this cohort. RD confers the greatest risk of incident vision loss, and once 25% or more of the retina is involved the risk of RD and visual loss increases significantly.