Temporal Raphe Sign for Discrimination of Glaucoma from Optic Neuropathy in Eyes with Macular Ganglion Cell–Inner Plexiform Layer Thinning

Abstract

To evaluate the potential of the temporal raphe sign on the macular ganglion cell-inner plexiform layer (mGCIPL) thickness map for discriminating glaucomatous from nonglaucomatous optic neuropathy (NGON) in eyes with mGCIPL thinning. Cross-sectional study. A total of 175 eyes of 175 patients with mGCIPL thinning on Cirrus (Carl Zeiss Meditec, Dublin, CA) high-definition OCT were retrospectively included. Glaucoma specialists and neuro-ophthalmology specialists evaluated the patients' medical records for diagnosis of glaucomatous optic neuropathy (GON) or NGON. Finally, by consensus, 67 eyes with GON and 73 eyes with NGON were enrolled. A positive temporal raphe sign was declared in patients in whom there was a straight line longer than one-half of the length between the inner and outer annulus in the temporal elliptical area of the mGCIPL thickness map. Decision tree analysis was performed to formulate a diagnostic model. Area under receiver operating characteristic curve (AUC) with sensitivity and specificity. The temporal raphe sign was observed in 61 of 67 GON eyes (91.0%), but in only 21 of 73 NGON eyes (28.8%) (P < 0.001; chi-square test). On this basis, the diagnostic ability of the temporal raphe sign for discriminating GON from NGON was judged to be good (AUC, 0.811; 95% confidence interval, 0.749-0.874; sensitivity, 91.0%; specificity, 71.2%). The diagnostic performance of the decision tree-based model (AUC 0.879; 95% confidence interval, 0.824-0.933; sensitivity, 88.1%; specificity, 87.7%) was better than that of the temporal raphe sign or the relative afferent pupillary defect (RAPD) alone (P= 0.005, P < 0.001, respectively; DeLong's test). The decision tree model revealed the following: (1) If the temporal raphe sign is positive and the RAPD is absent, the case should be diagnosed as GON; (2) if the temporal raphe sign is absent regardless of the presence or absence of the RAPD, or both the temporal raphe sign and the RAPD are present, the case should be diagnosed as NGON. In clinical practice, determining whether the temporal raphe sign appears on OCT macularscans can be a useful tool for discrimination of glaucomatous from nonglaucomatous mGCIPL thinning.