Noninvasive redox fluorometry: how light can be used to monitor alterations of corneal mitochondrial function.

Ultraviolet light can result in corneal, lenticular and retinal damage; however it can also be used (at much lower intensities) to measure the light induced alteration of cellular respiration and function. Mitochondrial function can be measured by noninvasive redox fluorometry which measures the intrinsic mitochondrial fluorescence of the reduced pyridine nucleotides (NADH + NADPH) and of the oxidized flavoproteins. Impaired mitochondrial respiration results in an increase in the reduced pyridine nucleotide fluorescence signal (366 nm excitation and 450 nm emission) and in a decrease in the oxidized flavoprotein fluorescence signal (450 nm excitation and 550 nm emission). These redox signals are sensitive to the cellular supply and utilization of oxygen and glucose as well as the mitochondrial work load. The effects of a reduced oxygen supply to the corneal epithelial surface can be measured. While redox fluorometry has been applied to the study of corneal hypoxia, it may also be used to monitor the effects of light induced damage to the lens and the retina. Noninvasive redox fluorometry is a sensitive technique to measure the effects of light on mitochondrial function in ocular tissue.