Early detection of retinal changes in children with diabetes without retinopathy using optical coherence tomography and optical coherence tomography angiography

To detect early retinal structural and microvascular changes in children and adolescents with diabetes mellitus (DM) without diabetic retinopathy (DR) using spectral-domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCTA), and to evaluate associations with glycemic control and disease duration. This study is a single-center, cross-sectional observational study conducted at a tertiary referral center. Three hundred participants aged 8–18 years were enrolled, comprising 150 patients with type 1 or type 2 diabetes mellitus and 150 age- and sex-matched healthy controls. All participants underwent comprehensive ophthalmic evaluations, which included ultra-widefield fundus photography, SD-OCT, and OCTA. Laboratory assessments included serum creatinine and serial HbA1c measurements, from which a time-weighted average HbA1c was calculated. The quantitative imaging parameters were recorded and analyzed. Quantitative imaging parameters included retinal thickness measured by SD-OCT, subfoveal choroidal thickness assessed through enhanced depth imaging, and vessel density within the superficial and deep capillary plexuses evaluated by OCTA. Foveal avascular zone (FAZ) parameters, including FAZ area, perimeter, acircularity index, and vessel density within a 300 µm-wide annulus (FD-300), were analyzed. The primary outcome was to compare ocular imaging parameters between the diabetes and control groups. Secondary outcomes involved evaluating associations between these imaging parameters and clinical variables, including diabetes duration and glycemic control. 148 individuals with diabetes and 150 healthy controls were enrolled in the analysis. Within the diabetic group, All patients showed no clinical evidence of diabetic retinopathy. Parafoveal retinal thickness in the superior (p = 0.02), temporal (p = 0.04), and nasal (p = 0.02) quadrants was significantly reduced in the diabetes group. FD-300 was also lower in the diabetic group (48.66 ± 3.57% vs 49.76 ± 3.91%, p = 0.01). Subgroup analysis revealed greater FD-300 reduction (p < 0.01) in those with diabetes duration exceeding 5 years. Furthermore, longer duration of diabetes was associated with reduced FD-300 values (r=-0.22, p = 0.007).This study identified retinal alterations in pediatric diabetes patients, including reduced parafoveal thickness and FD-300. The correlation between decreased FD-300 values and longer diabetes duration highlights its utility as a non-invasive biomarker for subclinical retinal involvement that precedes the development of clinical diabetic retinopathy.