Method and system for selecting a color filter, optical article comprising such a color filter

A method for selecting a color filter intended to be worn by a subject in order to improve his/her visual performance for a given visual task to be realized in a given environment, said method comprising the steps of:

• submitting said subject to a colored spatio-temporal visual stimulus adapted to evaluate said visual performance for said given visual task, said visual stimulus being designed to differentially stimulate the M and L cones stimulation pathways of the eyes of the subject so that its chromaticity may be modified and take at least two distinct values, the visual stimulus being generated by a color display;
• evaluating the visual performance of the subject based on his/her visual perception of said visual stimulus;
• and
• selecting said color filter based on the results of said evaluation of the visual performance, the selected color filter improving the visual perception of said visual stimulus
• wherein the visual stimulus VS presented to the subject is of the form:
• VS(x,y,t,λ)=C(λ)*L(x,y,t), where:
• C(λ) is a spectral density of the visual stimulus;
• and
• L(x,y,t) represents spatial and temporal luminance profiles of the visual stimulus, said visual stimulus being two monochromatic sinusoidal signals S(x,y,t) presented to the subject during a predetermined time and having a spatio-temporal pattern as a function of space (x,y) and time (t),
• the spatial and temporal luminance profiles of the visual stimulus are predetermined according to the subject's need for the given visual task, said subject's need is based on an improvement of the visual performance of the subject, the method further comprises a comparison step consisting in comparing at least one of said visual performance evaluation results with a predetermined reference value, the selection of said color filter being further based on the result of this comparison
• the spatial and temporal luminance profiles of the visual stimulus are predetermined according to the subject's need for the given visual task;
• and
• the predetermined reference value is a value of visual performance previously evaluated using said selection method,
• said the spatial and temporal luminance profile L(x,y,t) is proportional to [1+c*S(x,y,t)], wherein the signal S(x,y,t) is such that S(x,y,t)=cos(2*π*ω*t)*cos(2*π*x/∧x)*cos(2*π*y/∧y), where ω is the temporal pulsation ω, ∧x and ∧y are the periodicities of the signal S(x, y, t) along a vertical and an horizontal directions, c corresponding to a smallest contrast required to visually perceive a given signal S(x,y,t), the periodicities ∧x and ∧y and the temporal pulsation w defining the subject's need.