Retinal oximetry can be measured with newly developed Oxymap (Oxymap ehf, Reykjavik, Iceland). Briefly, the device simultaneously acquires digital images at two wavelengths and automatically tracks retinal vessels on both images. Retinal vessel oxygen saturation is estimated by spectrophotometric analysis of light reflected from retinal vessels and from the immediately surrounding retina. Oxygen saturation measurements are made on major temporal arteries and veins. Briefly, the first and second degree vessels are used, with the addition of third degree vessels in images where peripapillary haemorrhage prevented analysis close to the optic disc. Vessel segments chosen for analysis are used consistently for consecutive measurements in the same retina.