We have created a special progressive power lens in the be 4ty+® XLS. It is a personalised progressive lens intended first and foremost for people whose pupil distance is very different from standard values. Pupil distance has a large impact on the usage of progressive power lenses, which is why it is the only personal parameter to flow into the complex calculation process for be 4ty+® XLS models.

be 4ty+® XLS lenses are manufactured using a state-of-the-art,

computer-controlled, free-form technology known as CNC High Speed Cutting.

be 4ty+® XLS – for a customised vision!

be 4ty+® XLS, the special progressive power lens

State-of-the-art technology for progressive people

Modern, computer-controlled, free-form technology allows the completely free design of customised surface forms. be 4ty+® XLS is the second progressive power lens to be manufactured by Optiswiss using this new technology.

The model be 4ty+® VIP is a fully customised progressive addition lens, and be 4ty+® XLS can be seen as a „light version“ of the VIP design. „Light version“ refers to the simple fact that the pupil distance is the only personal parameter that flows into the calculation process. For the vertex distance, bow angle, near object distance and pantoscopic angle average values will be used.

This innovative progressive power lens is available with two progression lengths to allow your customers greater flexibility in their choice of frame.

be 4ty+® XLS – for your customised field of vision!

be 4ty+® XLS lenses are manufactured on state-of-the-art machines.

be 4ty+® XLS was designed especially for people who value high quality, the latest technology and maximum wearing comfort. However, what makes this lens so special is that it is intended first and foremost for people whose pupil distance differs significantly from average PD values.

Design characteristics

The be 4ty+® XLS model is identical as the be 4ty+® VIP, which is based on successful be 4ty+®. The be 4ty+® XLS is the result of meticulous further developments to the existing design. The scientists concentrated their efforts on perfecting the inner progression.

Benefits such as:

• - A larger near zone than with front surface progression,

• - Reduced distortion in comparison to front surface progression,

• - No „rocking“ effects when changing between near and distance zones.

Progression has been adapted to suit the requirements of natural sight. The power increase starts below the distance centration cross. It has a wide scope and a smooth increase. Full power is reached in the upper part of the near measuring circle, thus enabling a large, stable near zone. A slow, smooth increase in progression allows the wearer to enjoy tireless sight with a wide distance zone.

Pupil distance

The pupil distance is a required component for designing a progressive power lens. It is, alongside addition and distance zone correction, the most important parameter for the evaluation of convergence. As soon as the pupil distance deviates from the average value (64 mm) it is no longer possible to achieve a satisfactory overlap between the fields of view. This applies to both the progression zone and the near distance range.

The illustrations below show just how much convergence and inset are influenced by pupil distance. If your customer has a large pupil distance (Figure 1), he will need greater convergence and an inset more towards the inside than a person with a small pupil distance (Figure 2).

Fig. 1: An XXL PD in comparison to a normal pupil distance.	Fig. 2: An XXS PD in comparison to a normal pupil distance.

Impact of extreme pupil distances on convergence

Large pupil distance (XXL PD)

Figure 1 shows the convergence line for a normal progressive power lens. The overlap between the convergence line and astigmatic border area is quite clear. This causes aberrations which limit the field of view and make it no longer fully utilisable.

 Fig. 1 : conventional progressive lens

Figure 2 shows the convergence line of a be 4ty+® XLS. The field of vision are much wider, and the inset is displaced inwards to accommodate greater convergence. The result is an enjoyable, relaxed seeing experience.

Fig. 2 : be 4ty+ XLS

Optimum fields of vision to make sure you don‘t miss a thing!

Small pupil distance (XXS PD)

Figure 3 shows the convergence line with a conventional progressive power lens. Again, there is a clear overlap between the convergence line and the unfocused border area. This again causes aberrations, just as with a large pupil distance, that limit the fields of view in the progression zone and at close range.

Fig. 3 : conventional progressive power lens

Figure 4 shows the perfectly positioned convergence line of a be 4ty+® XLS. This enables optimum utilisation of each range and provides the wearer with an enjoyable, fatigue-free seeing experience.

Fig. 4 : be 4ty+ XLS

Complexity of the calculation method

The ultramodern method used to calculate be 4ty+® XLS progressive lenses is very complex on account of the many personal parameters that are included in the calculation. In addition, a mathematical optimisation process is used to produce a perfect progressive lens design. Around 40,000 measurement points on the surface flow into the calculation, and the exactitude of subsequent processing is in the μm range (1000th of a millimetre). This is achieved using state-of-the-art, computer-controlled, free-form technology known as CNC High Speed Cutting (HSC). This method allows unlimited, fully individual surface form designs.

The be 4ty+® XLS model range is based on this complex calculation method.

High-tech technology for total customer satisfaction.

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