EXPRESS: Retinochoroidal structural and microvascular changes assessed by Optical coherence tomography angiography in Obese Children: Association with Insulin Resistance Indices- A pilot study

Obesity-related chronic inflammation, together with dyslipidemia, promotes gradually progressive microangiopathy all over the body. Retinal vascular network is a mirror for systemic diseases induced vascular complications. We aimed to explore the association between choroidal thickness and retinochoroidal microvascular changes and insulin resistance indices [Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and triglyceride glucose (TyG) index] in obese children. This exploratory pilot comparative study included 20 obese children (BMI >95th percentile) and 20 healthy normal weight children (BMI >5th, <85th percentile for age and sex) as controls. Optical coherence tomography angiography (OCTA) 6×6 mm scans was used to measure central macular thickness (CMT), choroidal thickness, foveal avascular zone, choriocapillaris flow area, and retinal superficial/deep vessel densities (SVD/DVD) in parafoveal and perifoveal sectors. Anthropometric measurements, lipid profile, HOMA-IR and TyG index were assessed and correlated to OCTA parameters. Obese children had significantly lower visual acuity and thinner choroid compared to normal weight children. OCTA showed significant reductions in SVD and DVD across multiple para-/perifoveal sectors in obese than normal weight children. There are statistically significant negative correlations between Waist/height ratio, insulin resistance indices and OCTA parameters particularly at DVD. Effect size analysis showed high difference in TyG index, whole and parafoveal DVD between obese and normal weight children. In conclusion, obesity may contribute to subclinical retinal and choroidal structural changes beginning at DVD particularly in those with central obesity and insulin resistance. OCTA provides a noninvasive tool for detection of subclinical retinal vascular changes in children with obesity.