A method for measuring layer thicknesses of a multi-layer structure, wherein the multilayer structure is a tear film of an eye, the method comprising: generating a first two-dimensional image of the structure by, for each pixel of the first 2D image, generating a first incident light from a light source , measuring an intensity of a reflection of the first incident light at a location of the structure corresponding to the pixel; generating a second 2D image of the structure by, for each pixel of the second 2D image, generating a second incident light from the light source , measuring an intensity of a reflection of the second incident light at a location of the structure corresponding to the pixel; determining using a computer or like processor a thickness for at least one layer of the structure at each location of the structure based on the intensities of the measured reflections of corresponding pixels in the first and second 2D images, wherein the at least one determined layer thickness is a thickness of a lipid layer and a muco-aqueous layer of a tear film of an eye, wherein the first incident light is generated in a first discrete narrow spectral band, the second incident light is generated in a second discrete narrow spectral band, and the first and second discrete narrow spectral bands do not fully overlap, wherein the first and second discrete narrow spectral bands have bandwidths which are between a few nanometers to a few tens of nanometers at full width half maximum, to mitigate fringe washout and preserve thickness information of the thickest layer of the structure, and wherein the intensities of the reflection of the first and second incident light are measured by a light sensor . generating a first two-dimensional image of the structure by, for each pixel of the first 2D image, generating a first incident light from a light source , measuring an intensity of a reflection of the first incident light at a location of the structure corresponding to the pixel; generating a second 2D image of the structure by, for each pixel of the second 2D image, generating a second incident light from the light source , measuring an intensity of a reflection of the second incident light at a location of the structure corresponding to the pixel; determining using a computer or like processor a thickness for at least one layer of the structure at each location of the structure based on the intensities of the measured reflections of corresponding pixels in the first and second 2D images, wherein the at least one determined layer thickness is a thickness of a lipid layer and a muco-aqueous layer of a tear film of an eye, wherein the first incident light is generated in a first discrete narrow spectral band, the second incident light is generated in a second discrete narrow spectral band, and the first and second discrete narrow spectral bands do not fully overlap, wherein the first and second discrete narrow spectral bands have bandwidths which are between a few nanometers to a few tens of nanometers at full width half maximum, to mitigate fringe washout and preserve thickness information of the thickest layer of the structure, and wherein the intensities of the reflection of the first and second incident light are measured by a light sensor . <EOS>