Abstract
Purpose :
To investigate the characteristics of macular microvasculature of highly myopic eyes using optical coherence tomography angiography (OCTA) and identify their associations with structural parameters.
Methods :
Fifty highly myopic eyes from 52 subjects and 52 emmetropic eyes from 52 healthy controls were included. We measured the area of foveal avascular zone (FAZ) and the foveal and parafoveal vessel density (FVD and PVD, respectively) in the superficial(S) and deep(D) retinal plexus by OCTA (AngioVue). Ocular magnification of OCTA en-face images was adjusted with Bennett’s formula. Ocular characteristics, including best corrected visual acuity (BVCA), refractive errors, axial length, and OCT thickness parameters, were also reviewed. Correlations between these microvasculature measurements and ocular characteristics were analyzed.
Results :
Adjusted FAZ-S and FAZ-D was significantly large in myopic eyes.(all p<0.05). The FVD-S was significantly decreased(p<0.05) in myopic eyes whereas there was no significant difference in the FVD-D (p=0.16). As for retinal thickness, only parafoveal retinal thickness was significantly thinner (p<0.05). Axial length and parafoveal inner retinal thickness were significantly correlated with FVD-S (all P<0.05). Whereas subfoveal choroidal thickness was negatively correlated with axial length, choriocapillaries flow void area was correlated with neither axial length nor subfoveal choroidal thickness.
Conclusions :
The FAZ was enlarged and parafoveal vascular density was reduced in the highly myopic eyes. The decrease was prominent in SCP and well correlated with retinal thickness profiles. The macular microvascular network alteration may be attributed to ocular axial elongation that occurs with the progression of myopia.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.