Estimation of the Disc Damage Likelihood Scale in primary open-angle glaucoma: the Glaucoma Stereo Analysis Study

Purpose The Glaucoma Stereo Analysis Study (GSAS), a cross-sectional multicenter collaborative study, used a stereo fundus camera (nonmyd WX) to assess various morphological parameters of the optic nerve head (ONH) in glaucoma patients. We examined the associations between the Disc Damage Likelihood Scale (DDLS), a grading system for estimating glaucomatous ONH damage, and each parameter. Methods The study included 187 eyes of 187 patients with primary open-angle glaucoma or normal-tension glaucoma. ONH morphological parameters including the DDLS stage were calculated with prototype analysis software. Three independent graders classified each optic disc appearance into four different types: focal ischemic, myopic glaucomatous, senile sclerotic, and generalized enlargement. The correlations between the DDLS and patient characteristics or each ONH parameter were analyzed with Spearman’s rank correlation coefficient. Results The DDLS was correlated positively with baseline intraocular pressure and visual field pattern standard deviation, and negatively with visual field mean deviation. The DDLS was strongly correlated with vertical cup-to-disc ratio and horizontal cup-to-disc ratio positively, and with minimum rim-disc ratio negatively. The mean DDLS stage in the myopic glaucomatous type tended to be higher than the scores in other types. Conclusion The DDLS obtained through three-dimensional ONH analysis correlates well with the severity of glaucomatous ONH and visual field damage.