Effect of cytomegalovirus retinitis on the risk of visual acuity loss among patients with AIDS.

PURPOSE: To describe the prevalence and incidence of reduced visual acuity in eyes of patients with AIDS and without cytomegalovirus (CMV) retinitis at enrollment and estimate the proportion of incident vision loss attributable to new-onset CMV retinitis in this cohort.
DESIGN: Multicenter prospective observational study. PARTICIPANTS: Three thousand fourteen eyes of 1507 patients with AIDS and without CMV retinitis at enrollment.
METHODS: Medical history, ophthalmologic examination, and laboratory testing collected at enrollment and at follow-up visits every 6 months thereafter. MAIN OUTCOME MEASURES: Loss of visual acuity across the < or =20/50 and < or =20/200 thresholds and doubling of the visual angle; potential causes of this vision loss.
RESULTS: For eyes of patients without CMV retinitis at enrollment, the proportions with best-corrected visual acuity of < or =20/50 and of < or =20/200 were 3.9% and 1.8%, respectively. The incidence rates of vision loss to < or =20/50, < or =20/200, and to a doubling of the visual angle were 1.5/100 eye-year (EY), 0.8/100 EY, and 2.1/100 EY, respectively. Approximately 40% of the incident vision loss was attributable to CMV retinitis diagnosed during the follow-up period, and approximately 25% was attributable to cataract.
CONCLUSIONS: Although the development of CMV retinitis was the most common reason for visual acuity loss in eyes of our patients with AIDS, it accounted for less than half of the vision loss in our population (approximately 40%). Newly diagnosed cataract during the follow-up period accounted for a substantial amount of incident vision loss as well.