A system and method are described for performing tear film structure measurement. A broadband light source illuminates the tear film. A spectrometer measures respective spectra of reflected light from at least one point of the tear film. A color camera performs large field of view imaging of the tear film, so as to obtain color information for all points of the tear film imaged by the color camera. A processing unit calibrates the camera at the point measured by the spectrometer so that the color obtained by the camera at the point matches the color of the spectrometer at the same point. The processing unit determines, from the color of respective points of the calibrated camera, thicknesses of one or more layers of the tear film at the respective points. Other applications are also described.