Four patients with glaucoma-like discs, normal visual fields, and normal ocular pressures (less than 21 mmHg), first detected by direct ophthalmoscopy, were followed without treatment. Increased ocular pressures (greater than or equal to 21 mmHg) subsequently developed in these patients at an average of 8.1 years after the recognition of their glaucoma-like discs. Before the increased ocular pressure developed, two patients showed retinal nerve fiber layer loss and one showed optic disc hemorrhages. There are two possible hypotheses to explain this sequence of events. The first is that the optic discs and nerve fiber layer defects were produced by abnormal diurnal levels of ocular pressures or levels of ocular pressure, although less than 21 mmHg, which may be abnormal for the optic disc. The second hypothesis is that there are two independent events, one producing abnormalities in the optic disc and nerve fiber layer and a second producing the increased ocular pressure.