Device for determining a shift in a refraction value of an eye of a subject lighted by a light beam emitted by a light source, said shift being induced by an optical filter through which said light beam is transmitted to the eye of the subject, said device comprising one or more memories and one or more processors, wherein: - said one or more memories have in memory: one or more values of one or more initial spectral features of said light source, one or more values of one or more optical features of said optical filter, and a refraction shift model linking a magnitude associated with said shift and one or more spectral features of the light beam transmitted to the eye of the subject; and wherein - said one or more processors are programmed to perform the following steps: determining one or more values of one or more spectral features of said light beam transmitted to the eye of the subject through said optical filter based on said one or more values of one or more initial spectral features of said light source and said one or more values of one or more optical features of said optical filter; and determining said shift in the refraction of the eye of the subject based on said refraction shift model and said values of the spectral features of said light beam transmitted to the eye of the subject through the optical filter. - said one or more memories have in memory: one or more values of one or more initial spectral features of said light source, one or more values of one or more optical features of said optical filter, and a refraction shift model linking a magnitude associated with said shift and one or more spectral features of the light beam transmitted to the eye of the subject; and wherein one or more values of one or more initial spectral features of said light source, one or more values of one or more optical features of said optical filter, and a refraction shift model linking a magnitude associated with said shift and one or more spectral features of the light beam transmitted to the eye of the subject; and wherein - said one or more processors are programmed to perform the following steps: determining one or more values of one or more spectral features of said light beam transmitted to the eye of the subject through said optical filter based on said one or more values of one or more initial spectral features of said light source and said one or more values of one or more optical features of said optical filter; and determining said shift in the refraction of the eye of the subject based on said refraction shift model and said values of the spectral features of said light beam transmitted to the eye of the subject through the optical filter. determining one or more values of one or more spectral features of said light beam transmitted to the eye of the subject through said optical filter based on said one or more values of one or more initial spectral features of said light source and said one or more values of one or more optical features of said optical filter; and determining said shift in the refraction of the eye of the subject based on said refraction shift model and said values of the spectral features of said light beam transmitted to the eye of the subject through the optical filter.