Glaucoma Diagnostic Ability of Layer-by-Layer Segmented Ganglion Cell Complex by Spectral-Domain Optical Coherence Tomography

PURPOSE. To evaluate the diagnostic ability of layer-by-layer segmented macular ganglion cell complex (GCC) using spectral-domain optical coherence tomography (OCT) for detection of glaucoma and to analyze the topographic patterns of the segmented thicknesses in open-angle glaucoma. METHODS. Seventy-seven open-angle glaucoma patients and 59 healthy subjects were enrolled in this cross-sectional study. Spectral-domain OCT with automated segmentation was used to measure the separate thicknesses of macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL). We compared the specific diagnostic abilities of the GCC (RNFL+GCL+IPL), ganglion cell-inner plexiform layer (GCIPL: GCL+IPL), and circumpapillary RNFL (cpRNFL) to discriminate between normal eyes and glaucoma. RESULTS. The mRNFL, GCL, IPL, and cpRNFL thicknesses in glaucoma patients were all significantly thinner compared with healthy subjects and showed different topographic patterns. The GCC, mRNFL, and GCL thicknesses were best able to discriminate between the glaucoma and normal groups. The areas under the curve of receiver operating characteristics (AUROCs) of the mRNFL and GCL did not show significant difference from that of the cpRNFL. The AUROC of the GCL did not show significant difference from that of GCIPL after Bonferroni correction. The global IPL thickness had the smallest AUROC and showed lower diagnostic performance than the GCL, GCIPL, and GCC. CONCLUSIONS. The diagnostic ability of segmented mRNFL and GCL to discriminate between normal and glaucoma eyes is high and comparable to that of cpRNFL thickness. The measurement and monitoring of GCL could be a practical and effective approach to glaucoma diagnostics.