Gray Optic Disc Crescent: Evaluation of Anatomic Correlate by Spectral-Domain OCT

Abstract

To test the hypothesis that the anatomic correlate of the gray optic disc crescent is pigmentation of externally oblique border tissue of Elschnig. Retrospective study. African-American adult men with or without clinically apparent gray optic disc crescents. McNemar's test for paired data and kappa statistic with 95% confidence intervals were used to examine the relationships between eyes with or without gray optic disc crescents and corresponding spectral-domain (SD) OCT images with enhanced depth imaging (EDI). Correlation between clinical gray optic disc crescents and hyperreflectivity of externally oblique border tissue of Elschnig by SD OCT with EDI. Twenty-five eyes had clinically apparent gray optic disc crescents, of which SD OCT with EDI revealed hyperreflectivity (interpreted as increased pigmentation) of externally oblique (obtuse angle) border tissue of Elschnig in 22 eyes, that is, extending into Bruch's membrane opening and presumably visible by funduscopy. Thirty-two eyes from matched participants had no apparent gray optic disc crescent, of which SD OCT with EDI revealed hyperreflectivity of the border tissue of Elschnig in 23 eyes, but with a nonoblique (right angle) or internal (acute angle) angle, which would presumably obstruct funduscopic visualization. Observations by SD OCT with EDI suggest that the anatomic correlate of the gray optic disccrescent is pigmentation of externally oblique border tissue of Elschnig.