Surgical results in nystagmus blockage syndrome.

Sixty-four patients with nystagmus blockage syndrome (NBS) underwent surgery consisting of unilateral recession-resection, bimedial recession with and without posterior fixation suture, and bimedial recession with resection of one or both lateral recti. The results of the unilateral recession-resection and bimedial recession with or without posterior fixation were comparable. Over- and undercorrections occurred more frequently and the number of reoperations was higher than in a control group of essential infantile esotropia without nystagmus. These unpredictable surgical results in NBS present yet another feature that distinguish this condition from essential infantile esotropia without nystagmus. While restoration of normal binocular vision was not achieved in a single case, a functionally desirable result of subnormal binocular vision or microtropia occurred in 26%. An unusual complication consisting of postoperative asymmetric gaze nystagmus with an anomalous head posture was observed in five patients and required a Kestenbaum-Anderson operation in four to eliminate the head turn.