Progressive lenses are true masterpieces of optical technology. The upper part of the progressive lens is used for distance vision, and the lower part for near. The area between these two zones – is called the transition zone or the progression corridor – and ensures you enjoy clear vision in the complete viewing range from distance to near. The laws of physics inevitably lead to slight blurring in the periphery of this zone. The extent of this blurring depends on the quality of the progressive lens and on the degree of individualisation. The general rule is: the better the lens is tailored to the personal needs of each individual wearer, the less the peripheral blurring becomes. This decisively improves visual quality and wearer tolerance - and delivers the most natural vision possible.
ZEISS launched one of the first individually tailored lenses with the name Gradal® Individual on the market in 2000. This was a milestone in the history of optics. Then as today, the calculation and production of the lens incorporate not only the prescribed powers for the various ranges of vision, but also the personal parameters of the wearer such as the distance between the pupils, the fit of the frame on the face, the reading distance and other wearer parameters. This method of mathematical design and production has been constantly optimised over the years. These technological advances have been aided not only by faster and better methods of computation and production, but also by ongoing advanced research and development work at ZEISS. Only in this way has it been possible to produce a progressive lens surface with micrometre precision.
Every progressive lens surface is what is known as a freeform surface. This is made up of tiny surface elements that are locally variable but together create a smooth progressive surface. These elements are then mathematically adapted to the measured personal data of the wearer. This allows optimum matching of the vision zones to each wearer's personal needs, therefore simultaneously enhancing wearer tolerance to the lenses.