Reproducibility of Retinal Nerve Fiber Layer and Macular Ganglion Cell Layer Thickness Measurements by Optical Coherence Tomography in Myopic Eyes.

Abstract

In myopic eyes, reproducibility of circumpapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer thickness measurement by optical coherence tomography (OCT) showed excellent reproducibility except for the temporal quadrant RNFL thickness measurement. The aim of this study was to evaluate the long-term reproducibility of circumpapillary RNFL and macular ganglion cell-inner plexiform layer (GCIPL) thickness measurements using OCT in myopic eyes. Sixty-five eyes with moderate-to-high myopia (spherical equivalent <-3.0 D, myopia group) and 53 eyes with low-to-no myopia (spherical equivalent ≥-3.0 D, control group) without ocular disorders, such as glaucoma or retinal diseases, were included. Three serial OCT scans recorded at 1-year intervals were analyzed. Reproducibility was evaluated using within-subject SD (Sw), coefficient of variation (CVw), and intraclass correlation coefficient (ICC). Mean±SD refractive error was -0.30±0.80 and -6.26±2.45 D for control and myopia groups, respectively. The myopia group had thinner superior, inferior, and nasal quadrant RNFL, thicker temporal quadrant RNFL, and thinner GCIPL than the control group (P<0.05), except for the minimum and superotemporal GCIPL thicknesses (P>0.05). The myopia group had lower reproducibility in temporal quadrant RNFL thickness (Sw, 2.57 μm; CVw 3.27%; ICC, 0.979) than the control group (Sw, 1.80 μm; CVw 2.59%; ICC, 0.989), whereas in other sectors of RNFL and all GCIPL parameters, comparable reproducibility was observed between the 2 groups. Long-term reproducibility of RNFL and GCIPL thickness measurements in moderate-to-high myopia was comparable to that of low-to-no myopia, except RNFL thickness in the temporal quadrant. These findings should be considered when detecting RNFL and GCIPL changes.