AbstractDual wavelength retinal oximetry has proven to be a useful tool for detecting abnormal retinal vessel oxygen saturation in various diseases. Oximetry images are acquired in a similar fashion as regular fundus images. Oximetry calculations use light intensity measured from oximetry images. A ratio is taken of light intensity at and beside the retinal vessels. This means that the overall illumination of the image has less effect on the result. Despite the ratiometric approach, it is clear from experience and studies on cataract patients that image quality does influence oxygen saturation calculations. The challenge is to estimate or quantify image quality in a reliable manner and to control for image quality in all comparisons between healthy groups and patient groups. Commercial interest