All designs can be decantated up to 10 mm to guarantee most thinnest lenses. To develop a new progressive lens in a high-quality level, extreme complex and powerful optimization programs are necessary. To simplify, you have to imagine that the optimization program looks for a surface which combines two different spherical surfaces (distance and near vision) as even as possible. It is important, that the areas for distance and near view are developed as comfortable as possible with all required optical properties. Also, the transformed areas should be as smooth as possible, that means without big unwanted astigmatism. These easy looking requirements are practically very difficult to solve. A surface has, at a normal size of 80 mm x 80 mm and a point distance of 1 mm, 6400 interpolation points. If now each individual point gets the freedom to move within 1 mm about 1 um (0.001 mm) for the optimization, with 6400 x1000 = 6.400,000 you have an incredible high number of possibilities. This complex optimization is based on the ray tracing technology.