DELAYED VISUAL-EVOKED POTENTIALS IN ADULTS AFTER MONOCULAR VISUAL DEPRIVATION BY A DENSE CATARACT

Purpose, To study the effect of monocular visual deprivation caused by dense unilateral cataracts in adults. Methods, Visual evoked potentia ls have been recorded in 11 patients after removal of a dense unilater al cataract acquired in adulthood. These were compared with those from 8 control patients after removal of a mild lens opacity. Results, Vis ual evoked potentials recorded on the first day after removal of a lon gstanding, dense, unilateral cataract showed a marked delay to stimula tion of the operated eye compared to the unoperated eye. No delay was found in the operated or unoperated eye of control patients. Delays in the visual evoked potential returned to normal within approximately 3 months after surgery, with the exception of the two patients with the most longstanding cataracts in whom the delays persisted much longer. Conclusions. The adult central visual system is sensitive to visual d eprivation caused by a longstanding, dense, unilateral cataract. The c hanges found may be important in understanding the causes of intractab le diplopia, which sometimes occurs after the removal of such cataract s.