Amblyopia and congenital esotropia. Visually evoked potential measurements.

Amblyopia in patients with congenital esotropia was studied using visually evoked cortical potentials. In only four of 31 patients with esotropia and no abducting nystagmus was amblyopia detected before surgery. Postoperatively, 19 of these patients had amblyopia. In contrast, nine of the 11 patients with esotropia and nystagmus exhibited amblyopia before surgery. We conclude that amblyopia occurs infrequently in patients with congenital esotropia and no nystagmus until surgery reduces the angle of deviation and breaks down the cross-fixation reflex.