Presence of an Optic Disc Notch and Glaucoma

Abstract

To assess the prevalence and associations of a notch in the optic disc neural rim. Stereo-photographs from the Blue Mountains Eye Study were graded for the presence of a notch (defined as focal reduction in neural rim width associated with a change in the curvature of the rim for no greater than 4 clock hours). A notch was found in at least 1 eye of 205 participants (5.7%), and was bilateral in 51 (1.4%). Notch prevalence increased with age from 2.48% in participants aged <60 years, to 4.1% for ages 60 to 69 years, 7.98% for ages 70 to 79 years and 15.3% for ages 80 years or older. No sex differences were found. Notches were more frequent in eyes with myopia (odds ratio, OR, 1.98, 95% confidence interval, CI, 1.31-2.98) or beta-peripapillary atrophy (OR 2.20, CI 1.52-3.22). No associations were found with intraocular pressure, optic disc hemorrhage, or migraine history. After adjusting for other risk factors, a neural rim notch was strongly associated with glaucoma diagnosis (OR 21.2, CI 8.8-50.8). The sensitivity and specificity for glaucoma with visual field loss of finding a notch in either eye was 90.3% and 96.8%, respectively. The positive predictive value of a notch was 45.4% and negative predictive value 99.7%. A notch in the neural rim is a relatively infrequent sign in normal eyes but is very frequent in glaucoma. This sign has both good sensitivity and a positive predictive value for glaucoma.