2 Breakthrough by Bernard Maitenaz

2.2 Varilux 2, a totally aspherical design

The launch of Varilux 2 in 1972 was the next fundamental step in the history of the progressive lens. The design of this lens abandoned the prevailing idea for spectacle lens construction that the visual perception is mainly dominated by foveal and static vision. So a bifocal was considered up to that time as a good correction for presbyopic people and even Varilux was still characterized by almost spherical far and near vision parts. And for the same reason the lateral aberrations of a progressive lens made it unacceptable for some experts strongly influenced by the concept of point focal lenses, notably in Germany [3].

Surprisingly if one talks with people wearing PPL’s of modern design many of them do not perceive these aberrations. Bernard Maitenaz understood that that the lens designer had to take into account the whole complexity of the visual process, that it is not only static and foveal, but also dynamic and peripheral. The result of taking into account this global character was the creation of a totally aspheric design for Varilux 2. The new surface had excellent “orthoscopic” properties, that means that in the lens periphery it preserved the direction of vertical and horizontal lines, which are so important for orientation in our daily life. Low levels of astigmatism and aberration gradients guaranteed a high quality of dynamic vision. The experts called Varilux 2 a "soft" design with a low level of aberrations compared to the “hard spherical” surface of the first Varilux.

“Patent Varilux 2” (US 3 687 528): “optical modulation” and ”orthoscopy”

The new concept of Varilux 2 is laid down in a patent filed in France in September 1969 and which has the US patent number 3 687 528. In the upper part of the lens the curvature of the orthogonal sections increases in the periphery and decreases in the periphery in the lower part of the surface. In the marketing documents of the Varilux 2 launch this curvature change of the orthogonal sections is called “Optical Modulation” and in a first approximation the orthogonal sections were “evolutive conics” which means that from the top to the bottom of the lens the sections were flat ellipses, a circle, elongated ellipses, a parabola and hyperbolas.

Another patent application was filed in France in 1966 (US patent 3 785 724) which covers the progressive surface with asymmetric structure i.e. a particular surface and a separate manufacturing for the right and left lens. July 1972 is the application date in France of a further patent US 3 910 691 with extensive claims limiting the curvature difference (depending on the add power) between a point on the main meridian and the horizontally corresponding point of any section between the surface and a vertical plane parallel to the main meridian.

The overall aspheric design of Varilux 2 was an enormous progress, it was the birth of the modern progressive lens .The number of non adapts to the new soft lens was very small, primarily due the excellent peripheral and dynamic vision properties but certainly also thanks to the increased experience of the ECP’s in prescribing and centering PPL’s. So Essilor sales of progressive lenses increased strongly and reached about 3 million per year in 1975 [3], at a similar time when American Optical launched its progressive lens.

The order of magnitude of the potential market was about 100 million lenses, as a rough estimate shows. To penetrate the market with a new product is a slow process, particularly if there is only one manufacturer of the product on a market, where the distribution has very often its favorite supplier. But not only the opticians and ophthalmologists were increasingly convinced that the progressive lens was a superior solution for presbyopes, but also the other manufacturers discovered the new product as an excellent opportunity to upgrade their product portfolio.