Comparison of localized retinal nerve fiber layer defects in highly myopic, myopic, and non-myopic patients with normal-tension glaucoma: a retrospective cross-sectional study

BACKGROUND: The purpose of this study was to evaluate the relationship between patterns of localized retinal nerve fiber layer (RNFL) defects and the degree of myopia in patients with normal-tension glaucoma (NTG). METHODS: We retrospectively reviewed medical records of patients with high myopia (42 eyes; spherical equivalent [SE] < −6.0 diopters [D]), low to moderate myopia (93 eyes; SE −6.0D ~ and −0.5D), and emmetropia (65 eyes; SE −0.5D ~ +0.5D), all of which were diagnosed as having NTG with localized RNFL defects. On RNFL photographs, the proximity of the RNFL defect to the center of the fovea (angle I) and the sum of the angular width of the defects (angle II) were determined. The patterns of localized RNFL defects were then compared with respect to differences in angles I and II. RESULTS: Angle I was significantly smaller in the high myopia group than in the low to moderate myopia group (p = 0.028) and the emmetropia group (p = 0.044), while angle II was significantly larger in the high myopia group compared with the low to moderate myopia group and the emmetropia group (p < 0.001, p = 0.007). CONCLUSIONS: Among subjects with NTG, localized RNFL defects are wider and closer to the fovea in eyes with high myopia than those with low to moderate myopia or emmetropia.