Wide-field swept-source optical coherence tomography angiography in the assessment of retinal microvasculature and choroidal thickness in patients with myopia

Background/aims Pathological myopia (PM) is a leading cause of blindness worldwide. We aimed to evaluate microvascular and chorioretinal changes in different stages of myopia with wide-field (WF) swept-source (SS) optical coherence tomography angiography (OCTA). Methods This prospective cross-sectional observational study included 186 eyes of 122 patients who had undergone imaging between November 2018 and October 2020. Vessel density (VD) and vessel skeletonised density (VSD) of superficial capillary plexus, deep capillary plexus and whole retina, as well as foveal avascular zone parameters, retinal thickness (RT) and choroidal thickness (CT), were calculated. Results This study evaluated 75 eyes of 48 patients with high myopia (HM), 43 eyes of 31 patients with mild to moderate myopia and 68 eyes of 53 age-matched controls. Controlling for age and the presence of systemic hypertension, we found that HM was associated with decrease in VD and VSD in all layers on 12x12 mm(2) scans. Furthermore, HM was associated with a VD and VSD decrease in every Early Treatment Diabetic Retinopathy Study grid, with a larger decrease temporally (beta(VD)=-0.39, beta(VSD)=-10.25, p<0.01). HM was associated with decreased RT and CT. Reduction in RT was outside the macular region, while reduction in CT was in the macular region. Conclusion Using WF SS-OCTA, we identified reduction in microvasculature and structural changes associated with myopia. Decrease in VD and VSD was greater in the temporal quadrant, and reductions in RT and CT were uneven across the retina. Further work may help identify risk factors for the progression of PM and associated vision-threatening complications.