Evaluation of the glaucomatous damage on retinal nerve fiber layer thickness measured by optical coherence tomography

Abstract

Purpose To evaluate the relationship between visual field and retinal nerve fiber layer (RNFL) thickness measured by optical coherent tomography (OCT) and to assess the diagnostic ability of OCT to distinguish between early glaucomatous or glaucoma-suspect eyes from normal eyes. Design Retrospective, non-randomized, cross-sectional study. Methods A total of 160 eyes of 120 normal Japanese adults, 23 eyes of 16 patients with ocular hypertension, 38 eyes of 35 glaucoma-suspect patients, and 237 glaucomatous eyes of 140 glaucoma patients were enrolled in the study. The glaucoma group included 89 early glaucomatous eyes. Thickness of the RNFL around the optic disk was determined with three 3.4-mm diameter circle OCT scans. Average and segmental RNFL thickness values were compared among all groups. The correlation between mean deviation and RNFL thickness in glaucomatous eyes was also analyzed. Receiver operating characteristic (ROC) curve area was calculated to discriminate normal eyes from early glaucomatous or glaucoma-suspect eyes. Results A significant relationship existed between the mean deviation and RNFL thickness in all parameters excluding the 3-o’clock area. The average RNFL thickness had the strongest correlation in all parameters (r = −0.729, P < .001). Retinal nerve fiber layer thickness at the 7-o’clock inferotemporal segment had the widest areas under the ROC curves in all parameters for early glaucomatous eyes (0.873). Conclusion Measurement of RNFL thickness by OCT is useful in detecting early RNFL damage. Furthermore, OCT measurements of RNFL thickness may provide clinically relevant information in monitoring glaucomatous changes.