Characterizing Vascular Wall and Lumen Caliber in Eyes with Diabetic Retinopathy Based on Adaptive Optics Scanning Laser Ophthalmoscopy

Abstract

(200/200) Purpose: Our aim was to evaluate structural alterations of retinal arterioles due to type 1 diabetes (T1D) and/or diabetic retinopathy (DR) under AOSLO imaging.

Methods: Each study eye underwent mydriasis and AOSLO imaging in a single-visit study. The instrument's arrangement of four offset aperture images provided two orthogonal split-detector images and enabled isotropic analysis of the arteriolar boundaries. For each arteriole, we calculated the wall-to-lumen ratio (WLR), mean wall thickness, and luminal and external diameters.

Results: In total, we enrolled 5 (20.8%) healthy control eyes and 19 eyes of patients with T1D. The DR distribution was: four (16.7%) no-DR, nine (37.5%%) mild or moderate nonproliferative DR (NPDR), and six (25%) severe NPDR or proliferative DR. Mean wall thickness increased significantly in eyes with T1D compared to healthy controls (p = 0.0006) and in eyes with more advanced DR (p = 0.0004). The WLR was significantly higher in eyes with T1D (p = 0.002) or more severe DR (p = 0.004). There was no significant relationship between T1D status or DR severity and any of the arteriolar diameters.

Conclusions: In this preliminary study, there appeared to be increases in the WLR and mean wall thickness in eyes with T1D and more severe DR than in the controls and eyes with no/less severe DR. Future studies may further elucidate the relationship between the retinal arteriolar structure and physiologic alterations in DR.

Keywords: adaptive optics; diabetic retinal disease; diabetic retinopathy; scanning laser ophthalmoscopy; vascular remodeling.

Figure 1

Magnitude of phase gradient (MPG) and standard deviation (STD) images of arterioles with delineated luminal (LD) (green) and external (ED) (magenta) boundaries. (A,B): Arteriole of a healthy control eye. (C,D): Arteriole of an eye with proliferative diabetic retinopathy (PDR).

Figure 2

Box plot for the mean wall thickness against DR distribution. The bottom and top lines of the boxes correspond to first and third quartiles, respectively; the middle lines refer to the median values, the diamonds to the mean values, and the whiskers to the standard deviations. The nonparametric test showed significant greater mean wall thickness as DR severity advances (p = 0.0004). Pairwise comparisons within the DR severity levels showed that that severe NPDR–PDR group had significantly increased thickness as compared to the healthy controls (p < 0.001) and mild–moderate NPDR group (p = 0.03). * Statistical significance; T1D: type 1 diabetes; DR: diabetic retinopathy; PDR: proliferative DR.

Figure 3

Box plot for the wall-to-lumen ratio (WLR) against DR distribution. The bottom and top lines of the boxes correspond to first and third quartiles, respectively; the middle lines refer to the median values, the diamonds to the mean values, and the whiskers to the standard deviations. The nonparametric test showed a significantly greater WLR as DR advances (p = 0.004). Pairwise comparisons within the DR severity levels revealed a significantly greater WLR in eyes with mild or moderate NPDR when compared with healthy eyes (p = 0.002). * Statistical significance; T1D: type 1 diabetes; DR: diabetic retinopathy; PDR: proliferative DR.