Thickness of Ganglion Cell Complex and Retinal Nerve Fiber Layer for High Myopia with Spectral-Domain Optical Coherence Tomography

Abstract

Objective: To analyze the thickness of the ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) in high myopia patients. Methods: In this cross-sectional study, RTVue spectral domain optical coherence tomography (SD-OCT) was used to analyze the thickness of the macular GCC and the peripapillary RNFL in 46 high myopia patients (46 eyes) and 31 control subjects (31 eyes) from November 2015 to July 2016 at Beijing Tongren Hospital. The high myopia patients were divided into three groups by axial length (AL): Group A (n=26, 26≤AL < 28 mm), Group B (n=12, 28≤AL < 30 mm), and Group C (n=8, AL≥30 mm). Comparisons between the groups were made by nonparametric Kruskal-Wallis H test. The relationship between GCC thickness or RNFL thickness and the AL in the high myopia groups was tested by the Pearson correlation test. Results: The thicknesses of the average, superior, and inferior GCC, and the average, superior, inferior, nasal RNFL were decreased in the high myopia group (H=20.38, 15.65, 21.69, 31.27, 20.10, 20.78, 11.08, all P<0.001). In contrast, the thicknesses of the focal loss volume (FLV) and global loss volume (GLV) were significantly increased in high myopia patients compared with normal controls (H=20.02, 27.24, all P < 0.001). There was a linear correlation between the AL and average GCC, superior GCC, inferior GCC, average RNFL, superior RNFL, temporal RNFL, inferior RNFL respectively (r=-0.462, -0.422, -0.462, -0.511, -0.502, -0.295, -0.408, all at P < 0.05). There was also a linear correlation between the refractive diopter and average GCC, superior GCC, inferior GCC, average RNFL, superior RNFL, temporal RNFL, inferior RNFL respectively (r=0.479, 0.469, 0.444, 0.604, 0.535, 0.413, 0.528, all at P < 0.05). The rate of change for RNFL thickness was significantly larger than for the GCC rate of thickness change (P<0.001). Conclusions: The thickness of the macular GCC in patients with high myopia is decreased. It is negatively correlated with the AL and positively correlated with the refractive diopter. The change rate of GCC thickness is significantly less than for the RNFL thickness change rate. Key words: myopic; ganglion cell complex; retinal nerve fiber layer; optical coherence tomography