Changes in the optic disk and retinal nerve fiber layer are the sole objective indicators of glaucomatous damages. Many investigators held that damages in the optic nerves in glaucoma preceded changes in the visual functions. The optic cups and visual fields of 106 primary open angle glaucoma eyes and 207 eyes of glaucoma suspects were followed up an average 16.6 months. Among 35 eyes that developed changes in the optic cup, the cup changes preceded the visual field changes in 78%, and both changes occurred simultaneously in 22%.