Abstract: The present invention relates to a method for measuring a distance to a target, comprising: a) supplying an excitation signal to a heating element in thermal contact with a thermo-optical material of a thermo-optical lens to change the focal length of said thermo-optical lens to focus on a target; and b) analysing said supplied excitation signal or a control signal originating the same, to determine, based at least on the magnitude of said analysed signal, a distance between said focused target and one of said thermo-optical lens and an optical element arranged in an optical path going from the target to the thermo-optical lens. A system and a computer program adapted to implement the method of the invention are also provided by the present invention.