Occult Macular Dystrophy
Patients with occult macular dystrophy (OMD) are usually middle-aged and have progressive loss of central vision or notice central scotoma, but no significant abnormality is seen in the fundus or fluorescein angiography. Optical coherence tomography (OCT) shows loss of the ellipsoid band in the central area (Fig. 19.1). Full-field electroretinography (ERG) is normal or may show diminished cone response; multifocal ERG reveals diminished amplitude in the central retina.