Essilor (Charenton, France) has investigated the existing correlations between the quality of wave fronts entering the eye and some subjective criteria of perception such as visual acuity and sensitivity to contrasts. The results of the experiments have led to the creation of a new lens concept based on the differentiated management of wave fronts according to the wearer’s needs in term of near, intermediary and far vision. In near vision, the posture adopted by the person may vary considerably according to the activity carried out, the surrounding environment, and the time of day. Moreover, posture changes from one individual to another, and so to be effective in all situations, a progressive lens has an enlarged area for near vision which is enlarged both horizontally and vertically. For Varilux physio, the use of wave fronts has made it possible to establish the optical characteristics of the lens in a very large area, both vertically and horizontally, and this is why the lenses are comfortable for near sight.
In the cases of intermediary vision, all the progressive lenses have a a residual astigmatism on both sides of the median line, a defect which is even greater the greater the prescribed addition. In the case of Varilux, the action deriving from the wave front has enabled the reduction of astigmatism and at the same time made it possible to orient the lens axis vertically, so as to perceive the visual field as larger. As far as distant vision is concerned, the defects (decrease in power and astigmatism) affect not only the quality of vision, but also all the serious defects, like coma for example. This type of defect is present in the far vision area also of progressive lenses but, thanks to the use of wave fronts, with Varilux coma control may be achieved. In this way defects are minimized for very large areas of far vision, including the mounting crossover area.
Found in Vedere International 2008