Pupil cycle time in optic nerve compression.

We measured pupil cycle time before and after treatment in 11 patients with compressive optic nerve disease. Nine patients had chiasmal tumors and two had optic neuropathy of Grave's disease. Pupil cycle time before treatment was abnormal in at least one eye of all patients and in each case, pupil cycle time improved or worsened in accordance with the response to treatment of the patient's visual acuity and visual fields. This suggests that the pupil cycle time may be used as a simple objective office test for following up patients with impaired optic nerve conduction as the result of optic nerve compression. This information is similar to that gained from visual evoked response and may be used together with other objective clinical data such as disk pallor, nerve fiber loss, and relative afferent pupillary defect.