A method for determining reflectivity of a tear film lipid layer of a patient and recommending a course of treatment based on the same. The method includes the steps of: measuring a tear film aqueous plus lipid layer relative reflectance spectrum using a wavelength-dependent optical interferometer converting the measured tear film aqueous plus lipid layer relative reflectance spectrum to a calculated absolute reflectance spectrum comparing the calculated absolute reflectance spectrum to a theoretical absolute lipid reflectance spectrum to determine a tear film lipid layer thickness and determining a reflectivity value for the tear film lipid layer thickness at a first wavelength of light corresponding to ultraviolet, violet, or blue light.
