Assessment of macular retinal thickness and volume in normal eyes and highly myopic eyes with third-generation optical coherence tomography

Abstract

Purpose: To compare the macular retinal thickness and macular volume between subjects with high myopia and non-myopia. Methods: This prospective nonrandomized, comparative study recruited healthy subjects with high myopia subjects, defined as a spherical equivalence (SE) over -6 dioptres (D) or AXL ≥ 26.5 mm and the best corrected visual acuity better than 20/25, and subjects with non-myopia, defined as an with SE between 1.5D and -1.5D and the BCVA better than 20/ 25. Optical coherence tomography was performed in each eye. Results: Eighty high myopic eyes and 40 non-myopic eyes were included. The mean age of the high myopic group and non-myopia group was 29.6 and 27.5 years old, respectively. The mean refraction was -9.27D in the high myopia group and -0.22D in the non-myopia group. The high myopia group had significantly greater mean retinal thickness in the foveola and fovea 1mm area than the non-myopia group (166 vs149 μm, P < 0.0001, 199 vs188 μm, P = 0.0063, respectively). However, the mean retinal thickness in the inner and outer macular area (superior, nasal, inferior, or temporal) of the high myopia group was significantly less than in the non-myopia group. In addition, the high myopia group had significantly smaller macular volume than the non-myopia group (P < 0.0001). Conclusion: This study demonstrated that the retinal thickness in individuals with high myopia is thicker in the foveola and fovea, but thinner in the inner and the outer macular region. The retina of individuals with high myopia had smaller macular volume than those with non-myopia.