Retinal oximetry technology

AbstractPurpose Disturbances in retinal oxygenation are believed to be involved in several eye diseases, among them retinal vessel occlusions, diabetic retinopathy and possibly glaucoma and age‐related macular degeneration. The technology to reliably and non‐invasively measure retinal oxygenation is emerging after decades of development.Methods Non‐invasive retinal oximetry utilises the fact that the colour of blood changes as oxygen saturation changes. The most reliable measurements can be obtained from the larger retinal vessels, while measurements of retinal capillaries need further development. Several instruments have been built for non‐invasive oximetry. They measure light absorbance of retinal blood vessels at two or more wavelengths and use the result to calculate retinal vessel oxygen saturation.Results Several research groups have shown that their instruments are sensitive to changes in retinal vessel oxygen saturation and that the measurements are reproducible. Oximetry has successfully been used to detect differences in retinal oxygenation in many diseases as well as responses to treatment or provocation tests. Accurate calibration is, however, difficult.Conclusion The current retinal oximetry technology can reliably be used to measure changes in retinal vessel oxygen saturation in the same eye with time. Oximetry can also easily measure differences in means between groups. Further development is needed to increase the accuracy of single measurements. Commercial interest