Optic Disc Morphology Of South Indians The Chennai Glaucoma Study

Abstract

Purpose: To report planimetric optic disc data for South Indians from a population-based study. newlineDesign: Population-based cross-sectional study newlineParticipants: 632 phakic participants of the Chennai Glaucoma Study with reliable, normal newlinefrequency doubling perimetry screening examinations, clear ocular media, and myopia lt-8.0 D, newlineif any. newlineMethods: Subjects underwent complete eye examinations including refraction, keratometry, newlinefrequency doubling perimetry (screening C-20-1), pachymetry, gonioscopy, grading of lens newlineopacities and optic disc non-simultaneous digital stereo-photography. Planimetry was performed newlineon photographs under stereo-viewing conditions using custom software by a single observer. newlineOptic disc area, cup area, vertical and horizontal disc and cup diameters, and rim width at newline12, 3, 6 and 9 o clock positions were measured. Torsion of the disc gt15 degrees, tilting, newlinemorphological type of cupping (as no cupping, steep cupping, partly sloping or fully sloping newlinetemporal rim) and presence of cilioretinal arteries was noted. newlineMain Outcome Measures: Optic disc size and shape, optic cup size and shape, neural rim size newlineand shape, cup-disc area and linear ratios were examined. The association of all the above newlineoutcomes with several ocular and systemic factors was studied. Asymmetry of the above optic newlinedisc parameters was studied in a sub-group where data of both eyes were available (n=565). newlineResults: Mean optic disc area in this study was 2.8 ± 0.5 sq mm. 2.5th and 97.5th percentiles for newlineoptic disc area were 1.9 and 4 sq mm respectively. No association with age, sex, refraction, newlinecentral corneal thickness, presence of occludable angles, height or axial length were noted. newline