Gray Optic Disc Crescent: Influence of Ethnicity in a Glaucoma Population

Abstract

To evaluate the prevalence of the gray optic disc crescent within a glaucoma population and the influence of ethnicity and other variables. Consecutive patients of white or African American ethnicity, seen in the Glaucoma Service of Yale Eye Center, were included in the study. The 2 ethnic groups were not matched for refractive error, age, or stage of glaucoma. Stereodisc photos, suitable for detailed evaluation of disc and parapapillary features, of 1 or both eyes were selected by 1 investigator. The photos were masked to the other 2 investigators, who independently interpreted the disc and parapapillary features. The prevalence of the gray crescent in the 2 ethnic groups was compared by chi analysis. Correlation with age, sex, refractive error, intraocular pressure, and the presence and degree of glaucomatous optic neuropathy were also analyzed. Of 225 patients (447 eyes), the gray crescent was seen in one or both eyes of 32 patients (14.2%), which included 21 of the 77 [27.3%, 95% confidence intervals (CI) 9.95] African Americans and 11 of the 148 (7.4%, 95% CI 4.23) whites. The difference in prevalence of the gray crescent between the 2 ethnic groups was significant (P<0.0001). The prevalence of the gray crescent did not correlate with age, sex, refractive error, intraocular pressure or the presence or degree of glaucomatous optic neuropathy. The gray optic disc crescent is a common finding within a glaucoma population, especially among persons of African heritage, but does not correlate with the presence or degree of glaucomatous optic neuropathy nor other patient variables.