EVOKED-POTENTIAL ANALYSIS OF VISUAL PATHWAYS IN HUMAN ALBINISM

Purpose: To explore the abnormal crossing of the retinogeniculate path ways in human albinos with visual-evoked potentials (VEPs). Methods: T he authors studied the symmetry of the topographic distribution of pat tern onset/offset VEPs over the posterior part of the scalp elicited b y monocular stimulation of each eye in 31 consecutive patients with di fferent 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 ip silaterally in 7 patients. In two patients, the responses had a symmet ric topographic distribution. In eight patients, the amplitude was so low that studying the symmetry was not possible. Conclusions: These fi ndings demonstrate a non-uniform pattern of asymmetry as a result of t he miswiring of the visual pathways in human albinism. Moreover, the t ow amplitude of the VEP recorded in a consecutive series of patients s hows the difficulty of the study of this phenomenon in a clinical sett ing.