Research on Peripapillary Retinal Nerve Fiber Layer Thickness in Myopic Children and Adolescents

Abstract

Objective: To establish a database of the peripapillary retinal nerve fiber layer (RNFL) thickness in myopic and emmetropic children; to analyze the thickness and distribution of the peripapillary RNFL topographical map in children and adolescents with different degrees of myopia; and to measure regional differences in the thickness of the peripapillary RNFL and the factors that influence it in myopic and emmetropic children. Methods: This was a population-based, cross-sectional study. The average thickness of the peripapillary RNFL in children 6-18 years old was measured by spectral domain-optical coherence tomography. Ophthalmic parameters and systemic parameters, including height, weight, body mass index, head circumference, chest circumference, waist circumference, and blood pressure were measured. The children were divided into different refractive groups based on spherical equivalent (SE). The thickness of the peripapillary RNFL in different quadrants under different refractive conditions and relevant influencing factors were analyzed. The correlation between the average RNFL thickness and all parameters was analyzed by a simple linear regression and multiple stepwise regression. Differences between the groups were analyzed by one-way analysis of variance. Results: The average thickness of the peripapillary RNFL in 1 056 myopic and emmetropic children was 104±10 µm. It was 107±9 µm for emmetropes, and 105±9 µm for mild myopes, 101±10 µm for moderate myopes, and 95±8 µm for high myopes. The RNFL in emmetropes was thicker than in mild myopes (P=0.007) and moderate and high myopes (P<0.001 each). The RNFL thickness was positively correlated with SE (r=0.25, P<0.001) and lens thickness (r=0.10, P=0.033). It was negatively correlated with axial length (r=-0.18, P<0.001), but not correlated with age, sex, or other parameters. In all subjects, the inferior temporal quadrant was thickest, 162±23 µm, and the nasal quadrant thinnest, 61±10 µm. The topographical distribution for each group was different. The infratemporal sector was the thickest, and the nasal sector was the thinnest. The thickness of the temporal peripapillary RNFL increased with an increase in the degree of myopia. In mild myopes it was 87±14 µm, and in high myopes it was 98±21 µm. The thickness in other quadrants changed in the opposite direction, especially the infranasal sector. Conclusions: The average thickness of the peripapillary RNFL was positively correlated with SE and lens thickness, and negatively correlated with axial length. The topographical distribution was different in each myopia group. The thickness of the temporal quadrant gradually increased with increased degree of myopia, while that of the other quadrants decreased. Key words: myopia; retinal nerve fiber layer; optical coherence tomography