The etiology is unknown. They occur at the level of the RPE and outer retina. They tend to cluster in the perimacular area and are less abundant outside the arcades. They may grow and become confluent. The fovea often appears yellow, orange or white and granular, with no foveal reflex.
Vitreous cells are common.
There sometimes is a transient afferent pupillary defect. On fluorescein angiography, the white spots appear as multiple deep pinpoint clustered areas of hyperfluorescence. With ICG angiography, the lesions are hypofluorescent. Interestingly, numerous hypofluorescent lesions may be seen clustered around the disc, though they aren't apparent on ophthalmoscopy or fluorescein. In the acute phase of the illness, the ERG may be depressed.