Longitudinal Changes in Macular Vessel Density in High Myopia on Optical Coherence Tomography Angiography

INTRODUCTION: The aim of the study was to quantitatively characterize the longitudinal changes in macular vessel density (VD) in eyes with high myopia using swept source-optical coherence tomography angiography (SS-OCTA). METHODS: A total of 108 high myopic subjects (axial length [AL] ≥26.0 mm) and 180 age-matched normal subjects were recruited and followed up for at least 1 year. Here, 6 × 6 mm SS-OCTA scans centered at the fovea were used to obtain measurements of macular VD in both the superficial capillary plexus (SCP) and deep capillary plexus (DCP). Linear regression analyses were performed to determine the independent factors associated with the change rates of parafoveal VD over time. RESULTS: High myopia group presented a great loss of VD in both SCP and DCP, whereas control group only showed a significant reduction of VD in the SCP (all p < 0.05). The decrease of VD in the parafoveal region of high myopia group was faster than that of control group (SCP, -2.81%/year vs. -1.05%/year, p = 0.002; DCP, -1.06%/year vs. -0.01%/year, p = 0.004), as well as in the inner and outer ring (all p < 0.05). Longer baseline AL was demonstrated to be significantly associated with faster reduction of parafoveal VD in both SCP (estimate, -0.49; 95% CI: -0.79 to -0.18; p = 0.002) and DCP (estimate, -0.22; 95% CI: -0.42 to -0.03; p = 0.025) in high myopia group. CONCLUSIONS: High myopes exhibited a faster reduction of VD in parafoveal region and in the inner and outer ring in comparison with healthy controls. Longer baseline AL was associated with greater loss of parafoveal VD in patients with high myopia.