Retinal oxygen saturation using a 3D-printed reflectance retinal oximetry prototype in diabetic patients with and without diabetic retinopathy and controls

Abstract

Purpose : Diabetic retinopathy (DR) is a leading cause of visual impairment worldwide. A simple, non-invasive screening system could be valuable in detecting DR, especially in primary care settings. Hence, we evaluated the retinal oxygen saturation (SaO₂) of diabetic patients with and without DR and controls using a 3D-printed reflectance retinal oximetry prototype.

Methods : An observational, analytical, and cross-sectional study was conducted. Thirty-four healthy eyes, 16 eyes of diabetic patients without DR, and 26 with DR were included. A non-mydriatic 3D-printed reflectance retinal oximetry prototype (developed at the Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla, México) was used to measure central (10-degree field) and peripheral (30-degree field) retinal SaO₂. Patients with best corrected visual acuity (BCVA) <2.3 logMAR (<20/4000 Snellen) or with vitreous hemorrhage, cataract, or other conditions that interfered with the measurements were excluded. Clinical data and BCVA were registered. Unpaired t-tests were performed to calculate differences.

Results : Comparing global (central and peripheral) retinal SaO₂, eyes with DR had lower SaO₂ than healthy eyes (mean: 95.365 vs. 95.424, p<0.001). Contrary to the previous finding, diabetic patients without DR had a slightly higher global SaO₂ than healthy eyes (mean: 95.444 vs. 95.424, p<0.001). In all three groups, the peripheral SaO₂ was lower than the central SaO₂. Eyes with DR had lower peripheral SaO₂ than controls (mean: 94.965 vs. 95.050, p<0.001). Consistent with the higher global SaO₂ found in diabetic patients without DR, a slightly higher peripheral SaO₂ was observed compared to healthy eyes (mean: 95.111 vs. 95.050, p<0.001). Comparing central SaO₂, diabetic patients with and without DR had lower SaO₂ than controls (mean: 95.766 and 95.777, respectively vs. 95.798, p<0.001).

Conclusions :
While instrumental variations could cause differences between the central and peripheral measurements, our results suggest that eyes with DR have a lower central and peripheral retinal SaO₂ than healthy eyes. Further investigations must be addressed for these parameters to be considered screening markers for DR.

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