Visual evoked potentials in successfully treated strabismic amblyopes and normal subjects

Purpose: To assess electrophysiological recovery in successfully treated strabismic amblyopes. Methods: Pattern reversal visual evoked potentials were recorded from 11 successfully treated strabismic amblyopes 7 to 11 years of age and 10 age-matched normal children using 12.5' and 50' checks. Results: Nine amblyopic eyes had recovered to a Snellen acuity of 6/6 or better, and the remaining 2 were 6/9 after patching. Comparison between the amblyopic and the fellow eyes showed significantly lower P100 amplitude for the amblyopic eyes with small checks (difference -16.7%; P<.02) and significantly longer latency with larger checks difference (+5.0%; P<.02). The P100 latencies to stimulation of both the amblyopic and fellow eyes by 125 checks were markedly longer than in normal subjects (amblyopic eye, +11.7%, P<.0001; fellow eye, +7.7% P<.002). Conclusions: Successfully treated amblyopic eyes showed significantly longer latency than did normal eyes with small check stimulation. However, the nonamblyopic fellow eyes also showed significantly longer latency than did normal eyes, suggesting altered central processing.