Association of myopia and parapapillary choroidal microvascular density in primary open-angle glaucoma

Abstract

Background/Aims To compare parapapillary choroidal microvascular (PPCMv) densities between myopic eyes with and without glaucoma. Methods In this retrospective study, OCTA images (4.5 × 4.5 mm) were obtained using a commercial spectral-domain OCTA system. PPCMv density was calculated in inner and outer annuli using customized software. Marginal model of generalized estimating equations was established to adjust for confounding factors and intraclass correlations. Results This study included 35 myopic eyes with glaucoma (MG), 96 non-myopic eyes with glaucoma (NMG) matched for visual field mean deviation, 37 myopic eyes without glaucoma (MNG), and 73 control eyes from three tertiary centers. The participant ages were (mean [standard deviation, SD]) 57.43 [11.49], 60.40 [10.07], 52.84 [9.35], and 54.74 [12.07] years. Inner and outer annular PPCMv densities (mean [SD]) decreased in the following order: control (0.15 [0.04] and 0.12 [0.04]), MNG (0.14 [0.08] and 0.12 [0.08]), NMG (0.09 [0.05] and 0.07 [0.04]), and MG (0.09 [0.04] and 0.07 [0.03]). The mean differences in PPCMv density between glaucoma groups (NMG and MG) and the control group (mean difference [95% confidence interval]) were −0.06 (−0.08 to −0.04, P < 0.001 for inner whole annular PPCMv density in NMG vs control) and −0.07 (−0.10 to −0.04, P < 0.001 for inner whole annular PPCMv density in MG vs control), consistent across all regions of interest (ROIs). No significant interaction was observed between glaucoma and myopia after adjustment for potential confounders (P > 0.112). Conclusions Parapapillary choroidal microvascular density attenuation tends to be greater in eyes with glaucoma than in eyes with myopia.