A system for determining a personalized value of an optical feature of a corrective ophthalmic lens which is intended to be worn in front of an eye of an individual for correcting his vision, the system including: a trial optical corrective device adapted to be place in front of an eye of an individual, the trial optical corrective device providing a correction to an individual complying with an initial value of an optical feature; an eyewear adapted to be placed in front of the trial optical corrective device worn by the individual and adapted to immerse the individual in a virtual environment, the eyewear being designed to present, in the virtual environment, a visual task to the individual adapted to determine an adjustment value; a processing unit programmed calculate a personalized value of the optical feature based at least on the initial value and the adjustment value.