Quantitative OCT Angiography of the Retinal Microvasculature and the Choriocapillaris in Myopic Eyes

Abstract

Purpose : To study the retinal capillary microvasculature and the choriocapillaris (CC) in myopic eyes using quantitative optical coherence tomography angiography (OCTA) analysis.

Methods : 3x3 macular OCTA images were obtained using the RTVue XR Avanti with AngioVue. Quantitative measurements of the retinal capillary microvascular layers and the CC were obtained using en face projection images. Vessel density and fractal dimension of the superficial and deep retinal capillary plexus, and area and density of flow reduction in the CC were analyzed, quantified and compared to an age-matched control group.

Results : Fifty eyes of 28 patients (15 female, 13 male) with myopia and thirty-four eyes of 20 age-matched healthy individuals were included. The vessel density and the vessel branching complexity using fractal dimension of the retinal capillary microvasculature were significantly lower in myopic eyes (P<0.001 and P=0.001). The number of flow void areas in the CC was lower (112.04 vs 139.09, P=0.002) but the total and average size was significantly higher (3.706±0.259 vs 3.592±0.192, P=0.038) compared to the healthy control group. Average choroidal thickness was less in the myopic group versus the normal control cohort (123.538±73.477 vs 246.97±41.745, P<0.05) and significantly less in eyes with lacquer cracks (LC) compared with myopic eyes without LC formation (P=0.003). There was no correlation between choroidal thickness and quantitative parameters of the CC in the myopic eyes.

Conclusions : The density of the retinal capillary microvasculature is reduced and the area of flow deficit in the CC is increased in eyes with greater myopia. The relevance of microvascular alterations in the setting of myopia warrants further study.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.