Method comparison of two non‐invasive dual‐wavelength spectrophotometric retinal oximeters in healthy young subjects during normoxia

• Published in: Acta Ophthalmologica
• Main Authors: Told, Reinhard, Boltz, Agnes, Schmetterer, Leopold, Garhöfer, Gerhard, Sacu, Stefan, Schmidt‐Erfurth, Ursula, Pollreisz, Andreas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: Iceland
• Online Access: http://dx.doi.org/10.1111/aos.13719; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Faos.13719; https://onlinelibrary.wiley.com/doi/pdf/10.1111/aos.13719

Abstract Purpose Spectrophotometric retinal oximetry is a non‐invasive technology for measuring oxygen saturation in arterioles and venules (SaO 2 , SvO 2 ). We compared two commercially available systems: the Oxymap T1 (Oxymap ehf., Reykjavik, Iceland) and the Dynamic Vessel Analyzer ( DVA , Imedos, Jena, Germany). Methods Twenty healthy adults were included after giving informed consent. Two measurement cycles 30 min apart, including Oxymap T1, DVA , arterialized capillary blood draw of the earlobe (ScO 2 ) and peripheral oxygen saturation using finger pulse oximetry (SpO 2 ) were scheduled. Results SaO 2 (p > 0.0004) but not SvO 2 (p < 0.05) was statistically significantly different between the retinal oximeters used. Agreement between devices using repeated SO 2 measurements resulted in a standard deviation ( SD ) of differences of 3.5% in retinal arterioles and 4.8% in venules. Bland–Altman plot using the mean of a participant's two measurements from each device showed an average mean difference of 4.4% (95% confidence limits of agreement: −8.6 to 17.4) and −3.3% (95% confidence limits of agreement: −28.8 to 22.2) for SaO 2 and SvO 2 , respectively. Comparison of mean SaO 2 and SvO 2 with mean ScO 2 and SpO 2 indicated that SO 2 measurements were generally higher in ScO 2 and SpO 2 . Conclusion This study shows very good repeatability for both devices, which is consistent with the literature. However, it does not show sufficient concordance between SaO 2 measurements from both devices, indicating that patients should be followed by one device only. Differences in absorbance wavelengths used and image post‐processing may explain the differences.