Abstract
Purpose :
It has been reported that oxygen saturation in retinal arterioles and venules is higher in patients with Alzheimer's disease compared to healthy individuals. Mild Cognitive Impairment (MCI) is often the first stage of Alzheimer's disease. The main purpose was to establish a novel biomarker for Alzheimer's disease useful in its earliest stages. In this study, retinal vessel oxygen saturation of patients diagnosed with MCI was compared to oxygen saturation in healthy controls.
Methods :
Retinal vessel oxygen saturation measurement was performed in 42 patients diagnosed with MCI and 42 healthy controls with a noninvasive retinal oximetry imaging using the Oxymap T1 oximeter (Oxymap ehf, Reykjavik, Iceland). The two groups were age and gender matched.
Results :
Oxygen saturation in retinal arterioles and venules was higher in patients with cognitive impairment in the stage of MCI compared to healthy controls. In arterioles it was 93.1 ± 3.7% vs. 91.1 ± 3.4% (mean±SD p=0.003) and in venules; 59.6 ± 6.1% vs. 54.9 ± 6.4% (p=0.001). The arteriovenous difference in oxygen saturation was lower in patients with MCI compared to healthy controls, 33.5 ± 4.4% vs 36.2 ± 5.2%, p=0.02.
Conclusions :
Einarsdottir et al (2016) reported statistically significant higher retinal arteriolar and venular oxygen saturation in Alzheimer's patients compared with healthy controls. This study confirms and adds to these findings. It indicates that oxygen uptake is decreased in the retina of patients with MCI compared to healthy controls. Retinal physiology may provide an objective biomarker to help with diagnosis of Alzheimer's disease at an earlier stage than possible before.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.