HEAD FREEDOM AREA OF AN OPTICAL LENS

A device for determining a head freedom area of an optical lens adapted for a wearer looking at a specific point in a scene through the optical lens comprises at least one input adapted to obtain optical lens data representing the optical features of an optical lens, to obtain wearing data and fitting data representative of the wearing conditions and fitting parameters of the optical lens, and to obtain a specific threshold value for an optical performance criterion; and at least one processor configured for determining the head freedom area that corresponds to the head positions of the wearer that provide optical performances greater than or equal to the specific threshold value when the wearer is wearing the optical lens in given wearing conditions upon given fitting parameters and looking at the specific point in the scene through the optical lens.