A group of nine glaucoma patients in whom home tonometry, with the self-tonometer, had previously demonstrated elevated intraocular pressure (IOP) peaks upon waking were asked to measure their IOPs when they awoke in the morning, 30 minutes later, and 1 hour later. This was repeated for 4 days and medication was taken only after the third measurement. Eight of the nine patients demonstrated a reproducible decrease in IOP ranging from 2 to 18 mmHg within 30 minutes. There are indications that the momentary IOP elevation is associated with wakening. This phenomenon raises interesting questions regarding IOP variations. It indicates that in certain cases significant IOP peaks disappear before the patient can reach the clinic and may have an effect on loss of vision.