In recent years, optical coherence tomography angiography (OCT-A) has improved our understanding of microvascular changes in myopic macular degeneration. Researchers from the Harvard Retinal Imaging Lab have continued that endeavor using widefield swept-source OCT-A to assess retinal microvasculature and choroidal thickness in myopia. The technology was able to indicate decreased retinal vessel density and decreased choroidal thickness in myopic patients. The team presented their results at the 2021 ARVO virtual meeting.
The study analyzed 186 eyes—75 with high myopia (spherical equivalent [SE] ≤-6.00D or axial length ≥26.5mm), 43 with mild/moderate myopia (-6.00D<SE≤-1.00D) and 68 age-matched controls. The team used the PLEX Elite 9000 (Zeiss) using 3x3mm, 6x6mm and 12x12mm scans centered on the fovea.
Highly myopic eyes were associated with increased foveal avascular zone perimeter in 6x6mm and 12x12mm scans and decreased circularity in all scans. High myopia eyes and mild/moderate myopia eyes were associated with decreased vessel skeleton density and vessel density in all slabs. Furthermore, high myopia eyes were associated with a decrease in every ETDRS subfield, with a larger decrease temporally in 12x12mm scans. High myopia eyes were also associated with decreased choroidal thickness in all scan sizes. The researchers did note that changes in choroidal thickness were unevenly distributed, with thinning most evident in the region between the central fovea and optic disc and superior nasal subfields.
The team suggested that further work may help identify risk factors for the progression of pathologic myopia and other vision-threatening complications. Nevertheless, they believe that retinal findings using OCT-A may offer further insight into structural changes in myopia that can contribute to vision loss.
Moon J, Garg I, Cui Y, et al. Application of widefield swept-source optical coherence tomography angiography in the assessment of retinal microvasculature and choroidal thickness in myopia patients. ARVO Meeting 2021.