Retinal Oximetry in a Healthy Japanese Population

<div><p>Purpose</p><p>To establish the normative database of retinal oximetry using Oxymap T1 in a healthy Japanese population, and study the reproducibility of the measurements in Japanese.</p><p>Methods</p><p>We measured oxygen saturation in the major retinal vessels with Oxymap T1 in 252 eyes of 252 healthy Japanese subjects. Fundus images acquired using Oxymap T1 were processed using built-in Oxymap Analyzer software. Reproducibility of retinal oximetry was investigated using 20 eyes of 20 healthy subjects.</p><p>Results</p><p>The mean retinal oxygen saturation of 4 quadrants in healthy Japanese was 97.0 ± 6.9% in arteries and 52.8 ± 8.3% in veins. The mean arteriovenous difference in oxygen saturation was 44.2 ± 9.2%. Both arterial and venous oxygen saturation were significantly lower in the temporal side of the retina, especially in the temporal-inferior vessels. However, the arteriovenous difference in oxygen saturation was limited in the 4 quadrants. Interphotograph, intervisit, and interevaluator intraclass correlation coefficients were 0.936–0.979, 0.809–0.837, and 0.732–0.947, respectively. In the major retinal arteries, oxygen saturation increased with age (r = 0.18, p<0.01), at a rate of 0.67% per 10 years. However, venous oxygen saturation showed no correlation with age.</p><p>Conclusions</p><p>This study provides the normative database for the Japanese population. The arterial saturation value appears to be higher than other previous studies. Mean retinal oximetry in 4 quadrants with Oxymap T1 has high reproducibility.</p></div

Association between Age and Oxygen Saturation in Major Retinal Vessels Measured by Oxymap T1.

<p>Association between Age and Oxygen Saturation in Major Retinal Vessels Measured by Oxymap T1.</p

Fundus images at two different wavelengths of light obtained by Oxymap T1 and the oxygen saturation map analyzed by Oxymap Analyzer.

<p>(<b>A</b>, <b>B</b>) Oxymap T1 simultaneously captures 50° monochrome images centered at the optic disc at two different wavelengths of light (570 nm and 600 nm). (<b>A</b>) 570 nm is the reference isosbestic wavelength that is insensitive to oxygen concentration. (<b>B</b>) 600 nm is the oxygen-sensitive wavelength. (<b>C</b>) Oxymap Analyzer automatically calculates the oxygen saturation in each selected vessel and produces a color oxygen saturation map. Retinal vessels with higher oxygen saturation are indicated with red to orange color. Green to purple color indicates the retinal vessels with lower oxygen saturation. (<b>D</b>) For the analysis, vessel selection was performed disc-centered, 1.5-to 3-disc diameters area and 1 disc diameter away from the disc margin.</p

Association between retinal oxygen saturation and age in healthy Japanese.

<p>(<b>A</b>) Mean oxygen saturation in major retinal arteries in 4 quadrants (r = 0.18, p<0.01). (<b>B</b>) Mean oxygen saturation in major retinal veins in 4 quadrants (r = -0.06). (<b>C</b>) Mean arteriovenous (A-V) difference in mean oxygen saturation in 4 quadrants (r = 0.19, p<0.01).</p

Correlation between Refractive Sphere, Age, or Vessel Diameter, and Oxygen Saturation in the Major Retinal Vessels.

<p>Correlation between Refractive Sphere, Age, or Vessel Diameter, and Oxygen Saturation in the Major Retinal Vessels.</p

Systemic and Ocular Characteristics of Healthy Japanese Recruited in the Current study.

<p>Systemic and Ocular Characteristics of Healthy Japanese Recruited in the Current study.</p

Oxygen Saturation in Major Retinal Vessels in a Healthy Japanese Population Measured by Oxymap T1.

<p>Oxygen Saturation in Major Retinal Vessels in a Healthy Japanese Population Measured by Oxymap T1.</p