Before, during, and after electroconvulsive therapy (ECT), intraocular pressure (IOP) was evaluated in ten patients with a negative history for ocular disease. IOP values were obtained using an applanation tonometer. IOP increased dramatically, returning to baseline within 90 s after completion of seizure activity. We conclude that the magnitudes of the IOP elevation, although not hazardous in nonglaucomatous eyes, could possibly compromise ocular functioning in patients with severe glaucoma despite the transient nature of this relative increase in IOP.