Evoked potential analysis of visual pathways in human albinism.
OBJECTIVE
To explore the abnormal crossing of the retinogeniculate pathways in human albinos with visual-evoked potentials (VEPs).


METHODS
The authors studied the symmetry of the topographic distribution of pattern onset/offset VEPs over the posterior part of the scalp elicited by monocular stimulation of each eye in 31 consecutive patients with different types of albinism.


RESULTS
Twenty-one patients had asymmetric responses, with the major amplitude recorded over the lateral part of the scalp contralaterally to the stimulated eye in 14 patients and ipsilaterally in 7 patients. In two patients, the responses had a symmetric topographic distribution. In eight patients, the amplitude was so low that studying the symmetry was not possible.


CONCLUSIONS
These findings demonstrate a non-uniform pattern of asymmetry as a result of the miswiring of the visual pathways in human albinism. Moreover, the low amplitude of the VEP recorded in a consecutive series of patients shows the difficulty of the study of this phenomenon in a clinical setting.
Bouzas
E A
EA
Ophthalmic Genetics and Clinical Services Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892.
Caruso
R C
RC
Drews-Bankiewicz
M A
MA
Kaiser-Kupfer
M I
MI
D000293:Adolescent; D000328:Adult; D000368:Aged; D016117:Albinism, Ocular / Q000503:physiopathology*; D016115:Albinism, Oculocutaneous / Q000503:physiopathology*; D002648:Child; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D005829:Geniculate Bodies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D012160:Retina / Q000503:physiopathology; D014795:Visual Pathways / Q000503:physiopathology*