Acircularity and circularity indexes of the foveal avascular zone in high myopia

Helong Piao,Sang Woo Park,Mi Sun Sung,Haowei Zhang,Yue Guo

doi:10.1038/s41598-021-96304-9

Abstract

This study explored the association between foveal avascular zone (FAZ) parameters and high myopia using optical coherence tomography angiography. We divided 106 eyes of 106 patients into quartiles based on the axial length. The upper quartile was then defined as the high myopia group (n = 27), while the lower quartile was the non-high myopia group (n = 26). The areas and minor axis lengths of superficial and deep FAZ, the perimeters and major axis lengths of deep FAZ were significantly larger in eyes with high myopia than in eyes with non-high myopia (P < 0.05). Inversely, the subfoveal choroidal thickness was significantly thinner in eyes with high myopia than in those with non-high myopia. Linear regression analyses showed that no significant correlation was observed between FAZ areas and acircularity and circularity indexes of FAZ in non-high myopia group. Conversely, FAZ areas strongly correlated with acircularity and circularity indexes of FAZ in high myopia group. We found that an increase in the FAZ area in highly myopic eyes was accompanied by a significant variation in FAZ acircularity and circularity indexes. Further research should address whether these findings are associated with future disease development in highly myopic eyes.

Highlights

Since myopia progression mainly affects the posterior pole of the retina through axial elongation, highly myopic eyes may show some characteristic changes in the FAZ
In the present study, we measured the acircularity index, circularity index, and other biomarkers of the FAZ to quantify the shape of the FAZ and determine whether FAZ deformation was significantly correlated with high myopia
We found that several FAZ parameters were larger in highly myopic eyes than in non-highly myopic eyes, and that the differences were even more pronounced in the deep FAZ layer

Summary

Introduction

Since myopia progression mainly affects the posterior pole of the retina through axial elongation, highly myopic eyes may show some characteristic changes in the FAZ. No other parameter showed any significant difference between the groups (acircularity index, circularity index, and axial ratio of the superficial and deep FAZ). The areas of the superficial and deep FAZ were not significantly correlated with the circularity index of the FAZ in the non-high myopia group.

Results

Conclusion