In a series of 3,968 consecutive autopsies, myelinated nerve fibers of the retina were presented in 39 (0.98%) cases and bilateral in three (7.7%) affected cases; thus, 42 (0.54%) of the 7,936 eyes examined were affected. Myelinated nerve fiber lesions appeared as white or gray-white striated patches corresponding in shape to the distribution of retinal nerve fibers and demonstrated frayed borders. Myelinated retinal nerve fibers were continuous with the optic nerve head in 14 (33%) and discontinuous with the optic nerve head in 28 (66%) affected eyes. By light microscopy and electron microscopy, myelinated retinal fibers were marked by a ganglion cell axon surrounded by concentric lipoprotein lamellae that formed the myelin sheath. Glial cells were often prominent near the myelin sheaths, but other components of the sensory retina were morphologically normal. Clinically, 32 patients with myelinated retinal nerve fibers had comparable overall features, visual field defects less extensive than expected on the basis of ophthalmoscopic appearance, and normal findings on fluorescein angiography. Four patients had a syndrome characterized by ipsilateral extensive myelinated retinal nerve fibers, anisometropic myopia, amblyopia, and strabismus.