Early retinal changes detected using optical coherence tomography angiography in youth with type 1 diabetes mellitus: A case-control study

BACKGROUND: Despite contemporary management, the incidence of diabetic retinopathy in adolescents during the first 2-5 years of T1DM remains unchanged, underscoring the need to better understand early retinal changes. In this study, we investigated early retinal changes in children with T1DM using optical coherence tomography angiography (OCTA). Incorporating a literature review of retinal changes in other age groups, we propose a model sequence of retinal changes in patients with T1DM. METHODS: In this prospective case-control study, conducted at National Taiwan University Hospital (NTUH) from 2021 to 2023, we prospectively recruited children with T1DM from a paediatric endocrinology clinic and control children undergoing routine eye examinations at the Department of Ophthalmology. All patients and controls underwent comprehensive ophthalmological examinations and OCTA. RESULTS: In the T1DM group, the average age at diagnosis was 7.39 ± 4.29 years, average diabetes duration was 5.0 ± 3.19 years, and average glycosylated haemoglobin level was 7.41 ± 0.92%. In the control group, the mean age was10.8 ± 4.31 years, ranging from 5 to 20 years old, and that of DM group was 12.27 ± 4.32 years (p=0.08). The T1DM group showed significant decreases in macular vessel density, particularly in the superficial and deep vascular plexuses. Full retinal thickness was greater in the perifoveal annulus in the T1DM group. Prepubertal onset of T1DM negatively impacted the superficial capillary plexus in both the parafoveal and perifoveal areas. Other DM factors did not significantly correlate with vascular parameters. CONCLUSIONS: Using OCTA, we detected early, clinically inapparent microvascular reductions in vessel density in children with T1DM, while retinal layer thickness remained preserved. These findings, along with previous literature, infer that microvascular alterations detectable by OCTA, structural changes on OCT may occur sequentially and prior to clinically visible structural changes.