Stargardt disease (STGD) / Fundus flavimaculatus (FFM) is the most common autosomal recessive macular dystrophy with an estimated prevalence of 1 in 10,000 individuals. STGD manifests in the first or second decade of life with decreased central vision, progressive bilateral atrophy of the retinal pigment epithelium, and the appearance of orangeyellow flecks distributed in the posterior pole, sometimes extending beyond the vascular arcade. A milder form of the same disorder, fundus flavimaculatus, has a later age at onset, slower progression, and more-widespread distribution of the flecks.
Cone-rod dystrophy (CORD) has an estimated prevalence of 1 in 40,000 individuals. Most patients experience visual loss, impaired color vision, and a central scotoma early in life. During the initial stage of disease, the fundus may be normal or show fine macular lesions and pallor of the optic disc. In the later stages, the fundus shows pigmentary deposits resembling bone spicules, frequently in the macular area. Cone-rod dystrophy is characterized by more severe cone degeneration, which in the electroretinogram (ERG), is distinguished by more distinctive reduction of the photopic cone bwave amplitude than the scotopic (rod b-wave) amplitude, compared to rod degeneration.