The metabolic function of inner retinal cells relies on the availability of nutrients and oxygen that are supplied by the retinal circulation. Assessment of retinal tissue vitality and function requires knowledge of both the rate of oxygen delivery and consumption. The purpose of the current study is to report a novel technique for assessment of the inner retinal metabolic rate of oxygen (MO(2)) by combined measurements of retinal blood flow and vascular oxygen tension (PO(2)) in rat. The application of this technology has the potential to broaden knowledge of retinal oxygen dynamics and advance understanding of disease pathophysiology.