1. A method for determining a condition of a tissue, the method comprising: illuminating a tissue with light at an excitation wavelength; detecting a first and second intensity of received electromagnetic radiation from the tissue upon illumination at said excitation wavelength, wherein the first intensity corresponds to a first wavelength and the second intensity corresponds to a second wavelength different from the first wavelength; normalizing the first and second intensities with an intensity corresponding to an isosbestic point; and determining a condition of the tissue based at least in part on the normalized first and second intensities.