Papillomacular bundle and inner retinal thicknesses correlate with visual acuity in nonarteritic anterior ischemic optic neuropathy.

Abstract

To evaluate the ability of the papillomacular bundle (PMB) retinal nerve fiber layer and macular inner retinal layer thickness measurements with Spectralis optical coherence tomography (OCT) to differentiate eyes with nonarteritic anterior ischemic optic neuropathy (NAION) from uninvolved eyes and to evaluate whether their thicknesses correlate with visual acuity. An observational, cross-sectional study was performed, including 29 eyes with NAION and 29 uninvolved eyes from 29 patients. Eyes underwent scanning with Cirrus OCT (peripapillary and macular scanning) and Spectralis OCT (N-site axonal peripapillary scan and a new automated segmentation macular scan to measure individual retinal layers) in both eyes. The NAION eyes showed significant thinning versus uninvolved eyes in the macular retinal nerve fiber (P < 0.05), ganglion cell layer (GCL; P < 0.001), and inner plexiform layer (IPL; P < 0.01) by Spectralis and in the GCL-IPL by Cirrus (P < 0.02). Average and sectors of peripapillary retinal nerve fiber layer (pRNFL) and total macular thickness (TMT) were significantly reduced in NAION eyes, with both Spectralis and Cirrus OCT (P < 0.05). Spectralis temporal (ρSpearman = -0.768; P < 0.001) and PMB pRNFL thicknesses (ρSpearman = -0.675; P < 0.001), as well as central macular IPL thickness (ρSpearman = -0.735; P < 0.001), correlated strongly with best corrected visual acuity (BCVA). Quadratic regression using outer nasal TMT by Cirrus OCT and temporal pRNFL thickness by Spectralis were the best models to predict BCVA. Macular segmentation by Spectralis and Cirrus OCT revealed inner retinal layer atrophy in NAION eyes. The temporal and PMB pRNFL thicknesses and central macular IPL thickness by Spectralis-OCT and outer nasal TMT by Cirrus were strongly correlated with BCVA in NAION eyes.