Corneal metabolic imaging by FAD autofluorescence lifetime

The final goal of this work is to develop an corneal microscope based on fluorescence lifetime imaging microscopy (FLIM) of the metabolic co-factor FAD. In several corneal pathologies metabolic alterations occur prior to the pathologic expression therefore the assessment of corneal cells metabolic state could be a great advantage. Here, we aim to demonstrate the feasibility of using FAD autofluorescence lifetime to assess corneal cells metabolic state. We found an increase in protein-bound FAD fluorescence lifetime and a decrease in this component relative contribution 48h and 72h after animal sacrifice. These results are in agreement with the expected decrease in cell metabolism which has also been confirmed by MTT assay. Although the results are promising, the number of animals per conditions must be increased and further in-vivo studies are required to fully characterize FAD fluorescence lifetime in corneal tissues.