Occult macular dystrophy (OMD) is an inherited or sporadic macular dystrophy characterized by progressive loss of macular function but normal ophthalmoscopic appearance. Patients with OMD have normal full-field electroretinograms (ERGs), but the focal macular ERGs (FMERGs) and multifocal ERGs are abnormal. OMD is inherited as an autosomal dominant trait. However, patients with sporadic disease have been also reported. Mutations in RP1L1 gene, which plays essential roles in the cone functions, are responsible for OMD.
