Abstract
Purpose :
To investigate changes of choriocapillary (CC) in diabetic eyes using optical coherence tomography angiography (OCTA).
Methods :
In the cross-sectional study, 110 diabetic eyes, including 50 with no diabetic retinopathy (DR), 8 mild non-proliferative DR (NPDR), 20 moderate NPDR, 19 severe NPDR, and 13 proliferative DR (PDR), and 43 age-matched non-diabetic control eyes, were enrolled, among which there were 22 DR eyes without diabetic macular edema (DME) and 38 DR eyes with DME. All eyes underwent 3 × 3 mm and HD 6 × 6 mm OCTA scan patterns and optical coherence tomography (OCT) scan centered on the fovea, and the images were evaluated. The vascular density (VD) of CC in different stage of DR were investigated. The correlation of VD between retina and CC were analyzed.
Results :
Significant differences of VD of CC between adjacent stages were noticed between mild and moderate NPDR in HD 6 × 6 mm OCTA scan pattern (P = 0.034), and between severe NPDR and PDR in both 3 × 3 mm and HD 6 × 6 mm OCTA scan patterns (P = 0.024, P = 0.006)(Figure 1. Upper row.). The VD of CC in DR eyes with DME was significant less than that in DR eyes without DME in both 3 × 3 mm and HD 6 × 6 mm OCTA scan patterns (P < 0.001, P < 0.001)(Figure 1. Bottom row). Spearman correlation test revealed a relatively higher correlation between the VD of CC and the VD of retinal superficial and deep capillary plexus in 3 × 3 mm OCTA scan pattern (r = 0.697, r = 0.693) than that in HD 6 × 6 mm OCTA scan pattern (r = 0.580, r = 0.640). Low or non-perfusion area of CC were shown in advanced DR eyes, and sometimes discontinuous external limiting membrane was noticed in corresponding areas (Figure 2. Areas above yellow line segments.). The thickness of CC or the thickness ratio of CC to choroid at fovea in OCT images showed no significant relationship with the severity of DR.
Conclusions :
Choriocapillary vascular density are significantly reduced in more advanced stages of diabetic retinopathy and in eyes with diabetic macular edema. Diffuse reduction of choriocapillary perfusion is shown in early stages of DR, and focal reduction is shown in advanced stages of DR. A larger OCTA scan area shows more changes of choriocapillary. Our study suggests that the use of OCTA provides quantitative information regarding choriocapillary perfusion.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.