Retinal Blood Oxygen Saturation Disturbances in Patients with Type 2 Diabetes

Abstract

Purpose: To assess disturbances in retinal blood oxygen saturation in patients with mild-to-moderate non-proliferative diabetic retinopathy (NPDR).

Methods: Non-invasive hyperspectral retinal (HR) imaging (H-8.5 HR Camera, Optina, QC, Canada) was acquired in five participants with mild-to-moderate NPDR (67±8.5 years) and eight age-matched controls (69.4±5.3 years). For each subject, six repeated retinal images were acquired at wavelengths of 586 and 605nm using the HRC. This technology has a custom-built mydriatic fundus camera with a tunable light source. It permits the acquisition of hyperspectral retinal images for multiple wavelengths, without flash and is able to transmit wavelengths of 400-1000nm with a bandwidth of 2nm. The diabetic subject group and age-matched controls were free from major cardiovascular disorders. Subjects with a history of thyroid disorders were also excluded.

Results: Retinal blood oxygen saturation in the arterioles of healthy controls was 91.88±1.2%, and in the venules was 55.34±2.8%. Retinal blood oxygen saturation for diabetic subjects with NPDR were significantly higher at 95.36±2.4% (p=0.007) in the arterioles and 62.54±3.4% (p=0.002) in the venules.

Conclusions: Retinal blood oxygen saturation was significantly higher in the diabetic patients than in the age-matched controls. This finding could be the result of reduced retinal blood flow or reduced oxygen utilization, or a combination of both, in the diabetic NPDR group with mild to moderate DR.

Keywords: 499 diabetic retinopathy • 550 imaging/image analysis: clinical • 688 retina