Retinal oximetry is affected in multiple sclerosis

Structural and physiological abnormalities have been reported in the retina in patients with multiple sclerosis (MS). Retinal oximetry has recently detected changes in retinal oxygen metabolism in Alzheimer's disease and mild cognitive impairment. Our goal was to determine whether oxygen saturation in retinal blood vessels of patients with patients is different from that of a healthy population.

Oxygen saturation of haemoglobin was measured in retinal blood vessels, using imaging with spectrophotometric noninvasive retinal oximeter. Eight MS patients with history of optic neuritis were measured and compared to 22 healthy individuals matched in age and gender.

Venular oxygen saturation was increased in patients with MS compared to healthy individuals (70.7 ± 3.4% versus 66.2 ± 4.7; p = 0.021, mean ± SD). The arteriovenous (AV) difference was lower in patients with MS compared to healthy (26.6 ± 3.6% versus 30.5 ± 4.8%; p = 0.049). There was no difference measured in arterioles when patients with MS (97.3 ± 1.7%) and healthy individuals (96.7 ± 2.8%) were compared.

Increased venular oxygen saturation and lower AV difference in patients with MS may indicate reduced oxygen uptake. This may be due to less oxygen demand following atrophy and may be a useful objective biomarker for MS. Further studies are needed to confirm and expand these findings.