Alternating skew on lateral gaze (Bilateral adducting hypotropia)

Three males and one female with alternating skew deviation are reported. All of them showed adducting hypotropia in the lateral gaze for less than one month, which resolved. Duction was full in each direction. Three had brainstem tumor and one had a history of viral encephalitis. All of them had accompanying pretectal signs, such as upward gaze palsy, defective pupillary reaction, and nystagmus. Patients with alternating skew with pretectal signs may need urgent surgical intervention.