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

## TL;DR

This study uses advanced imaging to show how myopia affects the choroidal layers of the eye, revealing changes in blood vessels and tissue.

## Contribution

The study introduces the use of ultra-widefield OCTA to analyze choroidal vascular and stromal components in different myopia severity levels.

## Key findings

- Choroidal thickness decreases significantly with increasing myopia severity, especially in the sub-fovea and macular regions.
- Choriocapillaris density increases with myopia severity in the macular region, while vascular volume declines.
- Stromal volume changes are most notable between moderate and high myopia, and axial length correlates with stromal volume.

## Abstract

This study investigates changes in vascular and stromal components of choroidal vascular layers using ultra-widefield optical coherence tomography angiography (OCTA).

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.

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).

Wide-field OCTA effectively highlights choroidal component changes associated with myopia severity, offering insights into its structural alterations.