The etiology is unknown. Patients often don't experience symptoms until macular involvement develops. They can present with central or paracentral scotomata or abrupt vision loss. You will see acute geographic white edematous lesions in the RPE and choroid. Some patients may initially present with macular involvement and no peripheral lesions.
Cells often appear in both the vitreous and anterior chamber.
Over weeks or months, the lesions evolve into atrophic scars with variable pigment hypertrophy and, usually, extensive atrophy of the RPE and choroid. Recurrent lesions often appear adjacent to old healed ones. During acute episodes, fluorescein shows early hypofluorescence and late staining in the acute lesion area. Healed lesions appear as window defects, owing to the atrophic nature of the scars. The ERG and EOG are usually normal.