In an ophthalmologic study of 90 children with symptomatic giardiasis, ocular alterations were found in 10. Eight of these subjects presented an extensive "salt and pepper" degeneration of the pigmented epithelium involving 360 degrees of the midperiphery of both eyes. In one of the eight children, the pigmented epithelium showed atrophic areas, and in another there was a small hard exudate in the left eye. Of 2 remaining of the 10 children with ocular alterations, 1 presented with slight decoloration of the temporal half of the optic disc, and the other was affected by chorioretinitis. After single-dose antiprotozoic therapy (tinidazole 50 mg/kg), parasitologic tests were negative in all subjects and remained so throughout a 1-year follow-up. However, the characteristic epithelial lesion remained unaltered in all eight children for the entire follow-up period, as well as the optic disc decoloration in the only observed case. The child affected by chorioretinitis recovered after 3 weeks of combined treatment with bethametasone plus deflazacort. In two control groups, 1 of 200 healthy children and 1 of 200 children with gastrointestinal symptoms but without giardiasis, no case of "salt and pepper" degeneration of the pigmented epithelium or other significant ocular alterations was found.