ear oximeter [AS, eare + Gk, oxys, sharp, genein, to produce, metron, measure] , a device placed over the earlobe that transmits a beam of light through the earlobe tissue to a receiver. It is a noninvasive method of measuring the level of saturated hemoglobin in the blood. As the amount of saturated hemoglobin alters the wavelengths of light transmitted through the earlobe, analysis of the light received is translated into percentage of oxygen saturation (SaO2) of the blood. See also pulse oximeter.