BACKGROUND: Retinochoroiditis is the most common ocular manifestation of 
congenital toxoplasmosis, but other associated ophthalmological pathologies can 
also occur. The aim of this study was to determine the nature of the latter in 
treated cases of the disease and to assess their impact on visual function.
METHODS: Four hundred and thirty consecutive children with serologically 
confirmed congenital toxoplasmosis were included in this study. Data were 
prospectively collected using standardized ophthalmological assessment forms. 
The presence of retinochoroiditis and of associated pathologies was ascertained, 
and their impact on visual function was assessed.
RESULTS: After a median follow-up of 12 years [range 0.6-26 years], 130 children 
manifested retinochoroiditis. We detected 22 foci of retinochoroiditis at birth 
and 264 additional ones during the follow-up period. Of these, 48 (17%) were 
active when first diagnosed. Twenty-five of the 130 children (19%) had other 
associated ocular pathologies. Of these, 21 (16%) had a strabismus, which was 
due to macular lesions in 86% of the cases; 7 (5.4%) presented with unilateral 
microphthalmia, and 4 (3%) with cataracts. Most of these events were detected 
after the onset of retinochoroiditis. None of the children presented with ocular 
involvement in the absence of chorioretinal lesions. Macular lesions occurred 
more frequently in children with associated pathologies (p<0.0001), and 
associated pathologies were likewise more common in individuals with macular 
lesions (p=0.0003). Visual impairment occurred in 31/130 cases, and in all but 3 
of these eyes it was due not to an associated pathology but to macular 
retinochoroiditis.
CONCLUSIONS: At the end of the follow-up period, ocular involvement existed in 
30% of the treated children with congenital toxoplasmosis. Associated eye 
pathologies were manifested less frequently than anticipated. They may occur 
later in life and are an indirect marker of the severity of congenital 
toxoplasmosis, but they do not have a direct impact on visual acuity. The 
overall functional prognosis of congenital toxoplasmosis is better than would be 
expected on the basis of literature findings, with only 2 of the 130 children 
suffering bilateral visual impairment.