Application of Widefield Swept-Source Optical Coherence Tomography Angiography in the Assessment of Retinal Microvasculature and Choroidal Thickness in Myopia Patients

Abstract

Purpose : In recent years, optical coherence tomography angiography (OCTA) has improved our understanding of microvascular changes in myopic macular degeneration. We performed a prospective cross-sectional study using widefield swept-source OCTA (WF SS-OCTA) to assess retinal microvasculature and choroidal thickness in myopia.

Methods : Patients with high myopia (HM; Spherical Equivalent (SE) ≤-6D or axial length ≥26.5mm), mild/moderate myopia (MM; -6D<SE≤-1D), and age-matched healthy subjects were imaged with PLEX Elite 9000 (Zeiss) using 3x3mm, 6x6mm, and 12x12mm scans centered on the fovea. Foveal Avascular Zone (FAZ) perimeter, area, and circularity, as well as vessel skeleton density (VSD), vessel density (VD), and choroidal thickness (CT) of entire retina, superficial, and deep slabs were analyzed using the ARI Network (Zeiss Portal).

Results : 186 eyes were analyzed; these eyes were categorized as 75 with HM, 43 with MM, and 68 age-matched controls. HM was associated with increased FAZ perimeter in 6x6 and 12x12 scans (P<.05, Table) and decreased circularity in all scans (P<.002, Table). HM and MM were associated with decreased VSD and VD in all slabs (P<.03, Table). Furthermore, HM was associated with a decrease in every ETDRS subfield, with a larger decrease temporally in 12x12 scans (β_VSD=-13.21, β_VD=-0.40, P<.001). HM was associated with decreased CT in all scan sizes (P<.03, Table). Changes in CT were unevenly distributed, with thinning most evident in the region between central fovea and optic disc and superior nasal subfields (P<.02, Figure C).

Conclusions : We identified decreased vessel density associated with myopia using WF SS-OCTA in a large, comprehensive cohort at a single center. We also observed regional differences including a greater decrease in VSD and VD in the temporal quadrant and uneven reductions in CT. Further work may help identify risk factors for the progression of pathologic myopia and other vision threatening complications.

This is a 2021 ARVO Annual Meeting abstract.

 

Table: Mixed effect multiple linear models results. β, regression coefficient.

 

Figure: A-B. Boxplots of VSD and VD values in superficial (SF), deep (D), and retina (R) slabs. C. Regression coefficients of change in CT of HM by ETDRS subfield. Significant P-values (P<.05) are highlighted in darker color.