Abstract
Purpose :
To characterize the vascular wall-to-lumen ratio (WLR) of the retinal arterioles in eyes across the spectrum of DR with AOSLO imaging based on simultaneous acquisition of multiple offset-aperture images that facilitate improved structural and functional evaluation of the retina.
Methods :
Each study eye underwent mydriasis and AOSLO imaging in a single-visit study. Instrument’s arrangement of four offset-aperture images provided two orthogonal split-detector images and enabled isotropic analysis of the arteries’ boundaries. Custom-made MATLAB programing was used to detect and delineate the lumen and wall of the retinal arterioles. Gradient maxima indicated the location of structural changes (edges) associated to the blood vessel wall boundaries. Standard deviation (std) images highlighted the blood flow through motion contrast and the edges of the flow shown in these images corresponded to the lumen boundaries. Segmentation of the gradient maxima and std images provided the inside and outside boundaries of the vessel walls and enabled calculation of the WLR ratio and other structural characteristics of the retinal vasculature.
Results :
Healthy control eyes (N = 4) and eyes of patients with diabetes (N = 10) were included in the study. There were 3 (21.4%) eyes with no DR, 2 (14.3%) with mild nonproliferative DR (NPDR), 3 (21.4%) with moderate NPDR, and 2 (14.3%) with proliferative DR (PDR). In this small cohort, the mean WLR was lower in nondiabetic and no DR eyes, increased in NPDR and decreased as the DR progressed to more advanced stages. [mean(SD): nondiabetic 0.11(0.009), no DR 0.13(0.02), mild NPDR 0.15(0.02), moderate NPDR 0.14(0.03), PDR 0.11(0.01)].
Conclusions :
AOSLO imaging allowed in-depth evaluation of the morphology of the retinal arterioles across the full spectrum of DR severity. In this preliminary study, there appeared to be increases in WLR in eyes with mild NPDR compared to eyes with either no DR or more severe disease. If these findings are validated in larger cohorts, future studies will address whether this pattern is associated with changes in blood flow, which is known to be slower in eyes with mild NPDR compared to those with less disease and more severe DR. Thus, this technique may provide insight into correlations between retinal vascular structure and physiologic alterations in DR.
This abstract was presented at the 2023 ARVO Imaging in the Eye Conference, held in New Orleans, LA, April 21-22, 2023.