EYE MANIFESTATIONS OF CONGENITAL TOXOPLASMOSIS

PURPOSE: To determine the natural history of treated and untreated con genital toxoplasmosis and impact of this infection on vision. METHODS: In this prospective, longitudinal study, 76 newborns were treated wit h pyrimethamine and sulfadiazine for approximately one year, and 18 in dividuals not treated during their first year of life entered the stud y after age 1 year (historical patients). RESULTS: Chorioretinal scars were the most common eye finding in all patients and were most common in the periphery (58% of treated and 82% of historical patients). Mac ular scars were present in 54% of the treated patients; 41% were bilat eral. Macular scars were present in 76% of the historical patients; 23 % were bilateral. Visual acuity in the presence of macular lesions ran ged from 20/20 to 20/400. Of the patients followed up from the newborn period and treated, 29% had bilateral visual impairment, with visual acuity for the best eye of less than 20/40. Causes for this visual imp airment in eyes with quiescent lesions included macular scars, draggin g of the macula secondary to a peripheral lesion, retinal detachment, optic atrophy, cataract, amblyopia, and phthisis. There were recurrenc es in both treated (13%, 7/54) and previously untreated historical pat ients (44%, 8/18). The total, median, and range of years of follow-up during which recurrences were observed were, for treated patients, 189 years (total), five years (median), and three to ten years (range) an d, for historical, untreated patients, 160 years (total), 11 years (me dian), and three to 24 years (range). New lesions occurred in previous ly normal retinas and also contiguous to older scars. Active lesions a ppeared to become quiescent within ten to 14 days after beginning pyri methamine and sulfadiazine therapy. CONCLUSION: Many children with con genital toxoplasmosis have substantial retinal damage at birth and con sequent loss of vision. Nonetheless, vision may be remarkable good in the presence of large macular scars. Active lesions become quiescent w ith treatment.