Glaucoma Detection Ability of Ganglion Cell-Inner Plexiform Layer Thickness by Spectral-Domain Optical Coherence Tomography in High Myopia

PURPOSE: To compare the glaucoma detection ability of macular ganglion cell-inner plexiform layer (GCIPL) thickness measured with Cirrus spectral-domain optical coherence tomography (SD-OCT) with that of peripapillary retinal nerve fiber layer (RNFL) thickness in high myopia. METHODS: In 49 highly myopic and 54 nonhighly myopic glaucoma patients--along with 78 healthy myopic subjects--two scans, including one macular scan and one peripapillary RNFL scan, were obtained using Cirrus SD-OCT. For 44 randomly selected glaucoma patients, three macular scans were taken for reproducibility measurements. The glaucoma detection abilities of macular GCIPL and peripapillary RNFL thicknesses were compared between the highly myopic and nonhighly myopic groups. Diagnostic power was assessed by area under the receiver operating characteristic (AUROC) curves and sensitivity. Repeatability was assessed by intraclass correlation coefficient (ICC) and coefficient of variation (CV). RESULTS: All of the macular GCIPL and peripapillary RNFL thickness measurements excepting the 3 o'clock peripapillary RNFL sector showed an AUROC over 0.5. The best parameters for discriminating normal from glaucomatous eyes were inferior RNFL (0.906) and inferotemporal GCIPL (0.852) thickness in the highly myopic group, and average RNFL (0.920) and minimum GCIPL (0.908) thickness in the nonhighly myopic group. The best peripapillary RNFL and macular GCIPL thickness parameters showed no statistically significant differences. All of the ICCs of the macular GCIPL ranged between 0.96 and 0.99, and the CV was <3%. CONCLUSIONS: In cases of high myopia, the glaucoma detection ability of macular GCIPL thickness was high and comparable with that of peripapillary RNFL thickness.