Early selective deep capillary plexus impairment at diagnosis in children with type 1 diabetes: an OCT angiography...

Retinal microvascular dysfunction may precede clinically visible diabetic retinopathy in children with type 1 diabetes mellitus (T1DM), but whether it is detectable at diagnosis remains unclear.

To evaluate retinal microvascular alterations at T1DM diagnosis using optical coherence tomography angiography (OCTA) and assess associations between deep capillary plexus (DCP) vessel density and metabolic severity.

This cross-sectional study included 50 children with newly diagnosed T1DM (100 eyes) and 50 age- and sex-matched controls (100 eyes). OCTA was performed using 6×6-mm macular and 4.5×4.5-mm optic disc scans. Vessel density (VD) was assessed in the superficial capillary plexus (SCP), DCP, and radial peripapillary capillary network. Foveal avascular zone metrics and retinal nerve fiber layer thickness were also analyzed. Linear mixed-effects models accounted for inter-eye correlation. Subgroup analyses were performed by HbA1c level and diabetic ketoacidosis (DKA) severity.

SCP VD did not differ significantly between groups. DCP VD was lower in T1DM eyes in the whole image (53.1±3.0% vs 54.6±2.8%, p=0.006), parafoveal region (54.0±3.1% vs 55.8±2.9%, p=0.002), and perifoveal region (53.4±3.0% vs 54.7±2.8%, p=0.02). Peripapillary VD and retinal nerve fiber layer thickness were similar. Higher HbA1c was independently associated with lower DCP VD, which also declined with increasing DKA severity.

DCP impairment is detectable at T1DM diagnosis before clinically visible diabetic retinopathy. OCTA may provide a sensitive, noninvasive biomarker of early retinal microvascular involvement in pediatric T1DM.