Prevalence, clinical characteristics, and causes of vision loss in patients with ocular toxoplasmosis

PURPOSE. To describe the prevalence, demographics, clinical features, and contributors to vision loss at presentation in a large cohort of patients with ocular toxoplasmosis seen at a tertiary referral center in northern California. METHODS. A retrospective review of the charts of 233 patients with ocular toxoplasmosis examined over 24 years. RESULTS. Ocular toxoplasmosis was diagnosed in 233 (8.4%) of 2761 patients with uveitis. The mean age at presentation was 27.2 years. Patients with ocular toxoplasmosis were more likely to be young (p<0.01), male (p<0.001), and Latino (p<0.001) as compared with patients in the entire uveitis cohort. At presentation, 159 patients (68.2%) had active disease, which was unilateral in all but one. Among the 160 eyes with active disease, 145 (90.6%) presented with a focal retinochoroiditis, 57.2% of which had an adjacent retinochoroidal scar. Atypical presentations occurred in 11 patients (6.9%). Of eyes with active disease, the main contributors to vision loss at presentation were intraocular inflammation (74.8%) and macular involvement (24.3%), whereas in eyes with inactive lesions the main contributors to vision loss were macular scar formation (67.9%) and amblyopia (11.3%). Younger age was the single significant predictor of macular involvement. CONCLUSIONS. Ocular toxoplasmosis is a common cause of uveitis. Our patients were more likely than general uveitis patients to be young, male, and Latino, often having emigrated from Mexico or Central or South America. The most common contributors to decreased vision in eyes with active lesions were inflammation and macular involvement, whereas in eyes with inactive lesions they were macular scar formation and amblyopia.