Abstract
Purpose :
Oxygen plays a central role in multiple physiological and pathophysiological processes, and retinal oxygen supply has been found to be an important factor in many ocular diseases. Zilia has developed an oximetry technology that allows oxygen saturation (StO2) measurements in targeted locations of the retinal tissue. The objectives of the study were to evaluate the stability of StO2 measurements over the period of acquisition, the repeatability of measurements at a given location, establish preliminary normative data, compare oximetry levels in individuals in different regions of the eye fundus.
Methods :
24 subjects (16 females, 8 males, age ranging from 19 to 83) were enrolled for this study. Acquisitions consisted of 10-sec measurements in 3 locations of the eye fundus: inferotemporal optic nerve head (ONH), macula and nasal retina. Four subjects were randomly selected for repeated measurements at the same locations in the same eye after 15-30-min breaks.
The minimum period of acquisition required to obtain reliable StO2 measurements was established. Paired T-tests were performed to assess repeatability and compare StO2 variations in the different regions of the fundus.
Results :
No significant difference was observed between 2 successive measurements at the same location (separated by 15-30 min breaks). Mean StO2 was 67.3%±5.57% in the ONH, 62.1%±4.69% in the nasal retina and 43.63%±10.97% in the macula. Significant differences in StO2 measurements were observed between the ONH tissue and the nasal retina (p<0.025), the ONH and the macula (p<0.0001), and the nasal retina and the macula (p<0.0001)
Conclusions :
Ocular oximetry offers a unique window into the retina and systemic health by means of examining hemodynamics. Until now, retinal oximeters have offered semi-quantitative information about the oxygenation in large superficial retinal blood vessels. However, to become useful in clinical settings, a technology enabling reproducible quantitative oxygenation measurements, both in the superficial blood vessels and the underlying capillaries present in the intervessel tissues, is desirable. The present study demonstrates the efficacy and reproducibility of the Zilia ocular oximetry technology towards measuring StO2 of the microcapillary network within the retina and the ONH.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.