Early retinal microvascular changes assessed with swept-source OCT-angiography in type 1 diabetes patients without retinopathy

Abstract

Purpose : Type 1 diabetes is a chronic disease affecting the young population and can lead to vision loss when diabetic retinopathy develops. Retinal microvascular alterations occur before the appearance of clinical signs on fundus examination. This study aims to describe and analyze retinal vascular parameters on optical coherence tomography angiography (OCT-A) in patients with type 1 diabetes but without diabetic retinopathy in comparison with non-diabetic volunteers.

Methods : This cross-sectional study was conducted at Dijon University Hospital from 2018 to 2020. Patients with type 1 diabetes without diabetic retinopathy constituted “the diabetes group” and non-diabetic participants the “the control group". Vessel density and foveal avascular zone were measured using 6 × 6-mm macular angiograms acquired with a swept-source OCT-A device. Blood glucose data were measured continuously for patients in the diabetes group equipped with a blood glucose sensor linked to a Freestyle Libre device to evaluate glycemic variability estimated by the Mean Amplitude of Glycemic Excursions (MAGE) score.

Results : In total, 98 patients and 71 volunteers were enrolled in a diabetes and a control group, respectively. A statistically significant lower vascular density of the inner circle was found in the superficial capillary plexus (SCP) in the diabetes group (β = 1.00 [95% CI, 0.468; 1.79], p = <0.01). There was a statistically significant correlation between central vascular density in the deep capillary plexus (DCP) and total daily insulin intake (r= 0.294 [95% CI, 0.00223; 0.539], p = 0.042); furthermore, use of the Freestyle Libre device was associated with higher vascular densities in both the SCP (β = 0.922 [95% CI, 0.226; 1.87], p = 0.034 for outer circle density) and the DCP (β = 1.92 [95% CI, 0.520; 3.24], p <0.01 for inner circle density, and β = 1.80 [95% CI, 0.427; 3.24], p = 0.023 for outer circle density). No association was found between retinal vascular parameters and MAGE score.

Conclusions : Retinal microvascularization is altered in type 1 diabetes even without clinical signs of diabetic retinopathy. Intensive glycemic control and optimization of diabetes management using a Freestyle Libre device seem to preserve retinal microvascularization.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.