Purpose: To compare the glaucoma diagnostic capabilities of optic nerve head (ONH) parameters with retinal nerve fiber layer thickness (RNFLT) using Cirrus spectral-domain optical coherence tomography (Carl Zeiss Meditec Inc, Dublin, CA; version 5.0.0.326).
Methods: Two hundred twenty-nine glaucomatous patients, 405 preperimetric glaucoma patients, and 109 healthy individuals were imaged by Cirrus optical coherence tomography optic disc cube mode. Correlations were sought between RNFLT and ONH parameters (disc and rim area, average and vertical cup-to-disc ratio, and cup volume). Areas under receiver operating characteristic curves (AUCs) of average RNFLT were compared with those of ONH parameters with respect to discrimination between glaucomatous patients and healthy individuals. Subgroup analysis was performed in early, moderate-to-advanced glaucomatous groups, glaucoma patients with a small disc area and a large disc area.
Results: Rim area showed the strongest correlation with average RNFLT (r=0.663) and the highest AUC (0.871). The overall AUC for discrimination between healthy individuals and glaucomatous patients was higher for average RNFLT than for rim area (0.957 vs. 0.871, P<0.001). In the early and small disc area subgroup, the AUC of average RNFLT was significantly greater than those of all ONH parameters. In moderate-to-advanced glaucomatous groups' patients, the AUCs of average RNFLT and rim area, in large disc area group patients, the AUC of average RNFLT and vertical cup-to-disc ratio, did not differ significantly.
Conclusions: RNFLT was better than any tested ONH parameter when used for glaucoma discrimination, especially in patients with early-stage glaucoma and in glaucomatous patients with small optic discs.