2.3. Evaluating optic disc and nerve fibre layer defects

Bilateral fundus photographs were captured using a 45 degree nonmydriatic retinal camera (NIDEK AFC-300; NIDEK Co., Ltd., Gamagori, Japan). As the fundus examinations were carried out by 3 different examiners (YK, KH, MY), each investigator independently evaluated the color photographs using CDSketch Version 1.4 2009–2012 (Kowa Company, Ltd., Nagoya, Japan). This software was used to screen for glaucomatous optic disc appearances. The rim border was determined based on shadows, gradations of color, texture, and the course of blood vessels. After the examiner manually drew a line on the disc and cup of the optic disc photo, the software calculated the vertical cup/disc ratio and rim width at the superior or inferior portion. When at least 1 examiner noted any findings that suggested the presence of glaucomatous changes, consensus was obtained in discussions, to make a final judgment. In general, we used right-eye optic disc photographs unless the image could not be evaluated, in which case the left-eye photo was used. All fundus photographs obtained from participants were included in the study analysis. The criteria for glaucoma diagnosis were based on previously reported diagnostic definitions for category 2 glaucoma and glaucoma suspects.^[17]