OCT Angiography of Chorioretinal Microvasculature in Children with Type 1 and Type 2 Diabetes without Retinopathy

To evaluate chorioretinal microvasculature using OCT angiography (OCTA) in children with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) without diabetic retinopathy (DR), compared with healthy controls.

A cross-sectional, observational study.

Subjects with T1DM and T2DM without DR were recruited from the pediatric diabetes center, and nondiabetic controls were recruited from the pediatric eye clinic from 2022 to 2024.

All participants underwent color fundus and 1050 nm swept-source OCTA imaging (3 × 3, 6 × 6, and 12 × 12 mm²). Quantitative OCTA analyses were performed using a custom MATLAB algorithm. Retinal segmentation was performed for the superficial retinal layer, the deep retinal layer, the whole retina, and the choroid. A linear mixed effects regression model was used to compare the results between youth with diabetes and controls, adjusting for age.

Mean values for retinal thickness, vessel skeleton density (VSD), vessel diameter index (VDI), mean choroidal thickness (MCT), choroidal vascularity index (CVI), choroidal vascular volume (CVV), and choriocapillaris thickness.

A total of 32 subjects (44% females, 57 eyes) were included as follows: 10 T1DM, 7 T2DM, and 15 without diabetes. For youth with T1DM, age was 16 ± 2 years, glycated hemoglobin was 7.7 ± 0.9%, and diabetes mellitus (DM) duration was 8.0 ± 4 years. For youth with T2DM, age was 16 ± 2 years, mean glycated hemoglobin was 8.7 ± 3.5%, and mean DM duration was 2.4 ± 1.3 years. Age for youth without diabetes was 12 ± 5 years. Choroidal vascularity index and CVV were significantly higher in T1DM compared with controls (CVI: 0.69 ± 0.04 vs. 0.63 ± 0.05, P = 0.001; CVV: 18.9 ± 5.0 vs. 16.2 ± 2.0 mm³, P = 0.001) but not in T2DM. Choriocapillaris thickness was also significantly higher in T1DM (9.5 ± 1.2 μm) compared with controls (8.4 ± 1.0 μm, P = 0.003), with no significant difference in T2DM. Retinal thickness, MCT, VSD, VDI, and flux were not different among groups (P > 0.05).

Children with T1DM without DR exhibited larger choroidal and choriocapillaris vascularity than controls and no contemporaneous differences in retinal vascularity measures. This suggests that subclinical choroidal changes are present in pediatric diabetic patients before clinical or subclinical signs of DR.

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