BACKGROUND: Retinochoroiditis is the most frequent manifestation of congenital 
toxoplasmosis. We aimed to describe the ocular outcome and factors that may 
influence the visual prognosis of these patients.
METHODS: Cohort of patients with confirmed congenital toxoplasmosis seen between 
1996 and 2017 in Porto Alegre, southern Brazil.
RESULTS: Seventy-seven patients were included, of which 65 (85.5%) were 
identified by routine screening. Median age at the end of the follow-up was 10 
years (minimum 2, maximum 25). Retinochoroiditis was present in 55 patients 
(71.4%). New retinochoroidal lesions developed after the first year of life in 
77.8% of the patients who began treatment after the fourth month of life, 
compared with 35.2% among those treated before 4 months of life (relative 
risk = 0.45, 95% confidence intervals: 0.27-0.75, P = 0.02) and 33.3% among 
those treated before 2 months of life (relative risk = 0.42, 95% confidence 
intervals: 0.25-0.72, P = 0.01). There was a peak incidence of new 
retinochoroidal lesions between 4 and 5 years and another peak between 9 and 14 
years, the latter only among girls. Thirty-four patients with retinochoroiditis 
were followed up for 10 years or more, and the school performance was 
appropriate in 28 (82.4%).
CONCLUSIONS: The high incidence of new retinochoroidal lesions during the 
follow-up period indicates the importance of long-term follow-up of patients 
with congenital toxoplasmosis. Initiating treatment within the first 4 months of 
life, especially within the first 2 months, was a protective factor against the 
later development of retinochoroiditis. Despite the usual favorable prognosis, 
the high morbidity of congenital toxoplasmosis in Brazil was confirmed.