Retinal Nerve Fiber Layer-to-Disc Ratio Distinguishing Glaucoma from Nonarteritic Anterior Ischemic Optic Neuropathy

Abstract

Purpose: To evaluate the diagnostic value of retinal nerve fiber layer-to-disc ratio (RDR) compared to established parameters including retinal nerve fiber layer thickness (RNFLT), Bruch membrane opening-minimum rim width (BMO-MRW), and Bruch membrane opening-minimum rim area (BMO-MRA) for differentiating between open angle glaucoma (OAG) and nonarteritic anterior ischemic optic neuropathy (NAION).Methods: This retrospective study included 23 optic disc size-matched normal control eyes and 23 OAG and NAION eyes matched according to global RNFLT. The RDR, RNFLT, BMO-MRW, and BMO-MRA were analyzed; the diagnostic capabilities of these parameters were compared using the area under the receiver operating characteristic curve (AUC).Results: The global BMO-MRW and total BMO-MRA were lower in the OAG group than in the other two groups (all <i>p</i> < 0.001). RDR was greatest in the OAG group, followed by the healthy and NAION groups (<i>p</i> < 0.001). Between the OAG and NAION groups, the AUCs for temporal inferior BMO-MRW, total BMO-MRA, and RDR were 0.987, 0.996, and 1.000, respectively; these were greater than the temporal inferior RNFLT (0.811; <i>p</i> = 0.005, <i>p</i> = 0.006, and <i>p</i> = 0.006, respectively).Conclusions: RDR could be one of the useful parameters for differential diagnosis in OAG and NAION.