Investigation of 3D choroidal components in myopic populations using ultra-widefield OCTA

PURPOSE: This study investigates changes in vascular and stromal components of choroidal vascular layers using ultra-widefield optical coherence tomography angiography (OCTA). METHODS: A cross-sectional study included 147 participants with varying myopia degrees, categorised as low myopia (70 eyes), moderate myopia (104 eyes), and high myopia (110 eyes) based on refractive status. The TowardPi Wide-field OCTA measured choroidal parameters, including thickness, choriocapillaris density, vascular volume, and stromal volume. Differences in these parameters were analysed among the three myopia groups. RESULTS: Choroidal thickness decreased with increasing myopia, notably at the sub-fovea (LM vs MM vs HM: 297.56 ± 83.19 μm vs 230.13 ± 77.35 μm vs 190.49 ± 70.24 μm, P < 0.001) and macular region (258.20 ± 67.40 μm vs 215.37 ± 56.07 μm vs 186.01 ± 49.10 μm, P < 0.001). Choriocapillaris density in the macular region increased with myopia severity (48.06 ± 1.36% vs 48.15 ± 0.99% vs 48.74 ± 1.11%, P < 0.001). Vascular volume declined most in the macular (LM vs MM: 5.98 ± 1.62 mm³ vs 4.21 ± 1.52 mm³, P < 0.001). Stromal volume changes were prominent between moderate and high myopia (MM vs HM: 6.59 ± 1.48 mm³ vs 6.12 ± 0.75 mm³, P < 0.001). Axial length correlated with stromal volume (R = -0.498, P < 0.001), while spherical equivalent correlated with choroidal volume (R = 0.474, P < 0.001). CONCLUSION: Wide-field OCTA effectively highlights choroidal component changes associated with myopia severity, offering insights into its structural alterations.