Resolution of cyclic esotropia with 5-year follow-up after brief Fresnel prism treatment.

Cyclic esotropia is a rare form of strabismus that is characterized by a recurring esotropic deviation, usually with a 48-hour cycle. On esotropic days, the patient has a constant deviation with suppression, followed by a day with straight eyes and good binocular function. We report a case of cyclic esotropia in which the cycling resolved with 2 months of Fresnel prism for the amount of the distance deviation on her "straight" days. Five years later, with low plus hyperopic correction, she remains with a stable esophoria and normal stereopsis.