Evaluation of optic nerve head and retinal nerve fiber layer in early and advance glaucoma using frequency-domain optical coherence tomography

Background Recent research has suggested that structural significant damage in the optic nerve head (ONH) and retinal nerve fiber layer (RNFL) may precede visual field loss. Optical coherence tomography (OCT) has become an important tool which has contributed to earlier and more accurate diagnosis of glaucoma over the past decade. RTVue OCT was the first frequency-domain OCT (FD-OCT) device to offer comprehensive glaucoma analysis including an RNFL thickness map and optic disc morphology. The aim of this study was to evaluate and compare the performance of FD-OCT for the detection of early and advanced glaucoma from normal eyes. Methods This was a cross-sectional study consisting of 63 normal eyes, and 37 with early and 41 with advanced glaucoma. All patients underwent RNFL thickness and ONH parameter measurements on the RTVue OCT. Glaucoma variables obtained from RTVue OCT were compared between the groups. Discriminating power for early glaucoma detection was expressed by using the analyses of area under the receiver operating characteristic curves (AUCs). Results All RNFL thickness and ONH parameters but disc area showed significant differences between the normal and the glaucoma groups, and the highest AUCs for RNFL thickness was average thickness (AUC = 0.816) and for ONH parameters was cup/disc vertical ratio (AUC = 0.782). They were the best parameters for discriminating normal from early glaucomatous eyes. Conclusions Frequency-domain OCT (RTVue OCT) may offer comprehensive analysis for RNFL thickness and ONH, which showed good diagnostic ability in distinguishing normal from glaucomatous eyes.