PURPOSE: To assess the impact of highly active antiretroviral therapy on the epidemiology of cytomegalovirus retinitis in patients infected with the human immunodeficiency virus (HIV). METHODS: In a study performed in a single center for infectious diseases, we compared the data collected in 1995 (without highly active antiretroviral. therapy) with 1997 data (with highly active antiretroviral therapy). RESULTS: In a comparison of 1997 with 1995 data, the mean CD4(+) cell count of patients with cytomegalovirus (CMV) retinitis was higher (169 +/- 150 CD4/mu l vs 15 +/- 47 CD4/mu l) (P = .05), and the relapses of CMV retinitis were less frequent: (17% vs 36%) (P = .02), Newly diagnosed CMV retinitis decreased from 6.1% (59 of 952 patients) in 1995 to 1.2% (nine of 726 patients) in 1997 (P < .0001), In 1997, patients with newly diagnosed or relapsing CMV retinitis had a lower mean CD4(+) (31 +/- 2) cell count than patients with no relapsing CMV retinitis (197 +/- 160) (P = .01). CONCLUSION: The incidence and recurrences of CMV retinitis decreased from 1995 to 1997, probably as a result of restored immunity while the patients were undergoing highly active antiretroviral therapy; however, the increasing frequency. of HIV resistance to highly active antiretroviral therapy justifies close ocular follow-up. (C) 1999 by Elsevier Science Inc. All rights reserved.