Lateral incomitancy in intermittent exotropia: cause and surgical therapy.

A hypothesis, previously proposed, of tight medial rectus muscles in conjunction with tight lateral rectus muscles associated with exodeviations as a cause of lateral incomitancy in intermittent exotropia is supported by clinical management. Three patients with these findings underwent bilateral medial rectus and lateral rectus recessions by means of the adjustable rectus recession technique. Primary position alignment was achieved, and rotations were balanced with the alleviation of the lateral incomitancy. The lateral rectus muscles were recessed an amount more than usual in order to compensate for the recession of the medial rectus muscles.