Cyclic oculomotor paralysis

Abstract

Cyclic oculomotor palsy is a rare condition that is usually either congenital or presents in early childhood. Its essential features consist of paralysis of the oculomotor nerve supplying one eye with cycles of involuntary spasm and relaxation of the sphincter pupillae, and usually also of some of the extra-ocular muscles supplied by the oculomotor nerve of the affected eye. Two further typical examples of the condition are reported. Its aetiology remains conjectural since no case has come to necropsy. Most authors conclude, however, that there is partial aplasia or destruction of the oculomotor nucleus sparing those ganglion cells which control the muscles involved in the cyclic movements and that there is also a supranuclear lesion allowing automatic rhythmic impulses originating in a diencephalic centre to act on the intact cells of the oculomotor nucleus and bring about the cyclical phenomena.