Characteristic correlations of the structure-function relationship in different glaucomatous disc types

Purpose To investigate the influence of the optic disc type on the overall and regional correlation between structure and function in open angle glaucoma (OAG). Methods We divided 144 eyes of 144 patients with OAG into four groups according to Nicolela et al.'s classification of optic disc type: focal ischemic (FI), myopic glaucomatous (MY), senile sclerotic (SS), and generalized enlargement (GE). We measured the circumpapillary retinal nerve fiber layer thickness (cpRNFLT) with the 3D OCT-2000 and the mean deviation (MD) with the Humphrey Field Analyzer in each group and determined the influence of the disc type on these parameters with the Spearman rank correlation. Results We found that cpRNFLT and MD were significantly correlated in the MY (r = 0.61, P < 0.001), GE (r = 0.62, P < 0.001), and SS groups (r = 0.52, P = 0.002), but not in the FI group (r = 0.25, P = 0.130). The region of the optic disc with the highest correlation coefficient between structure and function differed according to the disc type. Conclusions The correlation between cpRNFLT and MD varied according to the optic disc morphology in OAG. This suggests that different disc types have characteristic regional variations in the correlation between structure and function. The disc type should therefore be considered in investigations of the correlation between structure and function in glaucoma.