Patients generally become symptomatic (reduced vision and metamorphopsia) in the fourth and fifth decades. Vision loss is mild as in vitelliform 1 disease and only slowly progressive in most patients. One or sometimes more small, oval, and slightly elevated yellow lesions resembling an egg yolk may be seen in the fovea along with paracentral drusen and mild RPE changes. The fundus changes can appear any time in adult life but little is known about their nature history. The EOG light/dark ratio may be normal or slightly decreased and the ERG likewise can be normal or, in some cases, reveals rod and cone system abnormalities. Optical coherence tomography shows yellowish deposits between the neurosensory retina and the RPE with foveal thinning. Color vision has been described as normal. The visual field may show peripheral constriction or central scotomas. Choroidal neovascularization occurs rarely.
Variability in the clinical features often leads to misdiagnosis in individual patients who are sometimes considered to have age-related macular degeneration, retinitis pigmentosa, fundus flavimaculatus, dominant drusen, butterfly macular dystrophy, and pattern dystrophy.