In five families with vitelliform dystrophy of the fovea, electro-oculography was performed. All 24 ophthalmoscopically-affected individuals had a pathological electro-oculogram (EOG). The carriers of the pathological gene also proved to have a clearly pathological light/dark-ratio of the EOG, although their foveas were ophthalmoscopically normal. Fifteen carriers were discovered with the help of the EOG. The pathological EOG indicates that there exists a diffuse disturbance of the deeper retinal layers, possibly the pigment epithelium in individuals with vitelliform dystrophy of the fovea. In three cases multiple vitelliform lesions were found. In these cases the EOG was also disturbed. It is assumed that multiple vitelliform lesions and Braley's polymorphic macular degeneration are true variants of vitelliform dystrophy of the fovea.
Deutman AF. Electro-oculography in Families With Vitelliform Dystrophy of the FoveaDetection of the Carrier State. Arch Ophthalmol. 1969;81(3):305-316. doi:10.1001/archopht.1969.00990010307001