Abstract
Purpose :
Evaluating the neuroretinal structure and microvasculature in diabetic retinopathy (DR) is essential to understand the disease pathophysiology. We used optical coherence tomography (OCT) and OCT-angiography (OCTA) images on the macular area to assess the full retinal thickness (FRT) and vessel skeleton density (VSD) and evaluate their relationship in patients with and without DR.
Methods :
All subjects were recruited under an IRB-approved protocol. Retinopathy was assessed as mild non-proliferative DR (NPDR) or referable DR (moderate NPDR or worse). FRT and VSD were evaluated on 3x3 mm2 scans (AngioPlex 5000, Carl Zeiss Meditec, Dublin, CA, USA). The FRT was measured from the internal limiting membrane to the outer boundary of the retinal pigment epithelium (Iowa OCT Explorer 3.8, Iowa City, IA). Layer-specific VSD was calculated for the superficial and deep retinal layers by dividing the total blood vessel length with the total area in the skeletonized vessel map as previously described (Kim AY et al., IOVS 2017). The association between parameters were compared among the study groups using one-way ANOVA with Bonferroni post-hoc tests.
Results :
Twenty-eight control subjects (39 eyes, 55.3±8.9 yrs), 49 mild NPDR subjects (77 eyes, 58.8±10 yrs), and 26 referable DR subjects (34 eyes, 58.3±10.2 yrs) were evaluated. The FRT was significantly lower in the referable DR group compared to the control group (285±20 vs 295±15 µm, P=0.004), but not between the mild NPDR (290.72±16.28 µm) and control groups (P=0.399), nor between the mild NPDR and referable DR groups (P=0.090). The mean VSD was significantly lower in the referable DR group compared to mild NPDR and control groups (0.145±0.01 vs 0.153±0.01 vs 0.159±0.01, P <0.001). There was a significant correlation between FRT and VSD in control and referable DR groups (R=0.412, P=0.009 and R=0.367, P=0.033, respectively), but not in the mild NPDR group (R=0.223, P=0.051).
Conclusions :
VSD was found to be lower in both the mild and referable stages of DR, while FRT was found to be abnormal in the referable stage. Although both VSD and FRT were found to be affected in referable DR eyes, the correlation between the parameters was weaker than in control eyes, suggesting that microvascular and neuroretinal damage do not occur in a strictly proportional manner in DR and that other factors may contribute to the damage at different disease stages.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.