Partially pigmented vitreous cyst.

Free-floating iris pigment epithelial cysts in the vitreous are very rare. We report the case of a partially pigmented cyst found on routine examination in the vitreous of a 51-year-old asymptomatic patient. Usually, non-pigmented cysts are derived from the hyaloid system. Pigmented cysts, however, are derived from the iris pigment epithelium. When they are not dislodged, these cysts can be confused with iris melanoma or primary stromal cysts. Treatment is usually unnecessary, unless they become symptomatic