10 Years of Individualized Lenses with Freeform Technology from ZEISS

May 12, 2000 was a milestone in the history of eyeglass lenses: the first progressive lenses that could be fitted for each individual wearer were born – Gradal^® Individual from ZEISS. This technology for individualized production of progressive lenses has remained revolutionary to this very day and is providing increasing numbers of people with better vision thanks to larger ranges of vision and enhanced wearer tolerance. Over the past eighteen years Carl Zeiss Vision has continued to refine this technology and expand its product line.

ZEISS Individual lenses are calculated and produced to incorporate not only the lens power, but also the distance between the wearer’s pupils, the position of the frame in front of the eyes and the wearer’s own preferred reading distance. This made it possible to manufacture progressive lenses on a totally customized basis to provide better, “tailor-made”  vision.

With Gradal^®  Individual, Carl Zeiss Vision developed a progressive lens that featured revolutionary, new properties. Based on the prescription and fitting data measured by the eye care professional every Gradal^®  Individual progressive lens was individually computed for each individual wearer. This data was incorporated in mathematical computations at Carl Zeiss Vision, on the basis of which every lens was individually produced for each wearer.

This groundbreaking innovation continues today in the current generation of customized freeform lenses from ZEISS, called Individual 2.

The more exactly the position of the lens in front of the wearer's eye is defined, the better it can be taken into account from the outset, i.e., in the calculation performed before production. The usable ranges of vision become larger, thus further improving wearer tolerance as well. In this way, the lenses are optimized to provide the best possible visual conditions for the wearer. For example, the distance between the wearer’s pupils, or PD as this is also known, is an important parameter for lens production data. While the prescription power has a decisive influence on distance vision, PD is crucial to both distance and near vision. This is of key importance for a progressive lens that is designed to correct both distance and near vision, but was not given enough attention before the introduction of individualized lenses.

Freeform technology made possible what was previously considered to be impossible: the implementation of a truly individualized design. But what exactly is freeform technology?

All  progressive lenses  feature a reading power in the lower part of the lens. The upper part of the lens is used for distance vision, and the transition between the two zones – also known as the progression corridor – provides clear vision in the middle distance range. Due to the laws of physics, blurring occurs at the edges of this zone that may vary in its intensity depending on the quality of the progressive lens design and the degree of individualized fitting. The more individualized the calculation and production of a progressive lens, the smaller the peripheral areas of blurring become. This results in an improvement in vision and wearer tolerance.

A progressive surface is what is known as a freeform surface. At Carl Zeiss Vision small components of the surface are defined which are locally variable and lead to a smooth progressive surface. These surface components are adapted to the wearer’s prescription with the aid of mathematical calculations and are then manufactured. This means that the design of the lens can be individually tailored to the personal needs of the wearer.