To evaluate the usefulness of the retinal nerve fiber layer (NFL) appearance in the estimation of glaucomatous optic nerve damage, we examined 335 eyes of normal, glaucoma suspect, of glaucomatous patients. In eyes with field loss, 84% had NFL atrophy. In normal eyes, NFL atrophy was suspected in 3%. In glaucoma suspects, 13% of eyes had NFL defects. Defects in glaucoma suspect eyes were more often localized, compared with the diffuse atrophy found in eyes with visual field loss. The NFL abnormalities were seen in areas of the retina corresponding to the location of visual field defects with a high accuracy. The NFL examination is as sensitive in detecting eyes with field loss as the optic disc configuration and may help to identify which eyes are suffering optic nerve damage prior to field loss.