Asymmetric visually evoked potentials in human albinos: evidence for visual system anomalies.

Behavioral, anatomic, and electrophysiologic studies indicate that the nondecussated optic system is functionally incompetent and anatomically disorganized in albino animals. The number of nondecussated optic nerve fibers from the retina to the lateral geniculate nuclei, pretectal nuclei, and superior colliculi is significantly reduced in albino mammals, and the laminae of the dorsal lateral geniculate nucleus are abnormal. Visually evoked potentials were recorded from both hemispheres of human albinos of four different genotypes and from normally pigmented human beings under conditions of binocular and monocular illumination. There was a significant asymmetry between the evoked potentiab recorded from each hemisphere of monocularly illuminated human albinos, as compared to normally pigmented human beings. The data suggest that there is a disorganization of the nondecussated optic fibers in the human albino similar to that observed in other albino mammals. The abnormalities of the nondecussated optic system are apparently associated with several forms of albinism which result in retinal hypopigmentation.