Ocular dipping in anoxic coma.

Patients with anoxic coma had a cyclic, downward dipping motion of the eyes. The sign is different from ocular bobbing, seizure-related eye deviation, oculogyric crisis, and roving eye movement. Its distinguishing characteristics are slow downward with rapid upward movement, a nadir at the extreme of downgaze, and spontaneous roving horizontal eye movements. Based on necropsy findings in one case and lesions of the basal ganglia evident on computerized tomographic scan in another, it is proposed that cortical dysfunction with damage to the basal ganglia may cause ocular dipping.