Development and Validation of Non simultaneous Retinal Image Acquisition–Based Retinal Oximeter

The purpose of this study was to develop and validate a tool for the measurement of retinal oxygen saturation using a conventional fundus camera–based nonsimultaneous imaging technique. Retinal oximetry setup comprising a conventional Zeiss FF450IR fundus camera, dual wavelength band-pass filters of wavelengths 570 and 600 nm were used. Image analysis was performed using MATLAB R2013b. All the study participants underwent comprehensive eye examination, fundus examination, complete hemogram analysis, and evaluation of systemic hemodynamics. Fundus images were captured by a nonsimultaneous retinal oximetry. A total of 45 subjects were included in the analysis. Median age of the subjects was 21 years ranging from 19 to 34 years. The median retinal arteriolar and venular oxygen saturation was 94.7% and 55.8%. Comparison of retinal oxygen saturation between three visits showed no statistically significant difference for both arteriolar (p = 0.33)and venular oxygen saturation (p = 0.79). Intraclass correlation coefficients for test–retest, short-term, and day-to-day repeatability were 0.84, 0.90, and 0.86 for arteriolar oxygen saturation and 0.92, 0.98, and 0.98 for retinal venular oxygen saturation. Oxygen saturation in retinal arteriolar and venular blood vessels can be measured by nonsimultaneous image acquisition technique using a conventional fundus camera with good repeatability.