Detection of Localized Retinal Nerve Fiber Layer Defects with Posterior Pole Asymmetry Analysis of Spectral Domain Optical Coherence Tomography

Abstract

To investigate the diagnostic ability of posterior pole asymmetry analysis (PPAA) with spectral domain optical coherence tomography (SD-OCT) for detecting localized retinal nerve fiber layer defects (RNFLD). Eighty-four open-angle glaucoma subjects (84 eyes) with localized, wedge-shape RNFLDs by red-free RNFL photography and 122 eyes of healthy subjects were enrolled. The subjects were examined by SD-OCT to obtain circumpapillary RNFL (cpRNFL) thickness as well as PPAA. The PPAA provides a corresponding cell to cell comparison between hemispheres within the central 20° and presents the difference using gray scale. Area under the receiver operating characteristic curve (AUROC) was calculated. The sensitivity and specificity of PPAA to detect glaucoma with the localized defects were also examined using various criteria; two consecutive black cells (criterion A), three consecutive black cells (criterion B), and four consecutive black cells (criterion C). An AUROC of PPAA based on the number of black cells was 0.958 ± 0.013. The sensitivity and specificity of PPAA were 95.2% and 81.1% for criterion A, 83.3% and 92.6% for criterion B, and 69.0% and 98.4% for criterion C, respectively. The sensitivity and specificity of the cpRNFL thickness were 85.7% and 95.1%, respectively. SD-OCT PPAA detects localized RNFLDs with high sensitivity and specificity, which are comparable to the cpRNFL thickness profile of OCT. These findings suggest that the PPAA can be complementary to other tests for diagnosing glaucoma in patients with localized RNFLDs.