Clinical detection of abnormalities in central vision in chronic simple glaucoma using contrast sensitivity.

Visual defect was assessed by contrast sensitivity and perimetry in 50 patients with chronic simple glaucoma. Abnormal contrast sensitivity using static gratings was found in patients with full central fields (i.e. a field of 15 degrees or more around fixation for the 12e isopter). It appears that central vision is affected by nerve fibre damage in the early stages of glaucoma, even in the presence of full central fields and normal visual acuity. Contrast sensitivity using temporally modulated gratings was reduced in the glaucoma patients, although this was found to be a less sensitive measure of visual loss than static contrast sensitivity function. These findings are discussed, and it is suggested that static contrast sensitivity function provides a simple method for detecting early visual defect in glaucoma and ocular hypertension.