The lens for quality-conscious customers

State-of-the-art production and development technology has enabled Optiswiss to bring an innovative, personalised progressive power lens to the market. The be 4ty+® VIP, design takes into account physiological, anatomical and personal conditions to achieve an optimum field of view - even under aberrant physiological conditions.

be 4ty+® VIP combines all the benefits of the be 4ty+®. The optimisation process, however, adds additional personal parameters to the calculation:

be 4ty+® VIP is the lens of choice for the discerning and active presbyopic spectacle wearer. For people who value the best quality, the latest technology and unsurpassed comfort, and who want to live out their individuality to the full.

• - Pupil distance,

• - Vertex distance,

• - Bow angle,

• - Near object distance,

• - Pantoscopic angle,

• - 7 progression lengths.

These glasses turn every glance into a visual experience. be 4ty+® VIP!

Design characteristics

The VIP model is, of course, based on the successful be 4ty+®. The be 4ty+® VIP 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.

Why 7 progression lengths?

Strong tilt of head = shorter progression length	Light tilt of head = longer progression length

The be 4ty+® VIP model offers you a choice of 7 progression lengths. This broad selection means the choice of frames available to your customers will not be limited. The progression length also plays an important role with regard to the wearer‘s individual and habitual way of looking.

Give your customer something to read and observe how he holds his head. If he tilts his head significantly he will need a shorter progression length. However, if he tilts his head less and instead lowers his eyes then he will need a longer progression length.

Physiological and anatomical conditions

With the exception of correction values for distance and near zones, conventional progressive lens designs make use of average values. For instance, a pantoscopic angle of 9°, a bow angle of 5° and as small a vertex distance as possible would be aimed for to achieve an optimum field of vision. However, every person has their own individual way of looking. This makes the use of spectacles a purely subjective matter. Results depended on the frame and the customer‘s facial form, and were not always satisfactory.

Average values are not used for the be 4ty+® VIP; instead, calculations are based on values determined individually for each customer, such as pupil distance, vertex distance, pantoscopic angle, near object distance and bow angle. The result is a lens designed completely around your customer.

Personal parameters (1)

Pupil distance

The pupil distance (PD) is the most important parameter for assessing convergence. Standardised progressive lenses assume a pupil distance of 64 mm. The overlap of the field of vision with the near zone will not be satisfactory if the pupil distance differs from the assumed average value. This can cause the wearer sight problems.

Vertex distance

The vertex distance (VD) serves as a measurement for calculating the position of the lens in relation to the eye. The greater the vertex distance, the greater the inset and progression required.

Pantoscopic angle

Up until now it was necessary to try and achieve a pantoscopic angle (PantA) of 9° to ensure the largest possible field of vision through the corresponding viewing angle. Including the angle in the calculation for the be 4ty+® VIP lens makes it possible to achieve an optimum near vision zone with both small and large pantoscopic angles.

Bow angle

The situation with the bow angle (BA) is similar to that of the pantoscopic angle. Any deviation between the bow angle and the assumed average value will change the viewing angle and can lead to aberrations. Furthermore, both vision fields are unequal due to the mutual change on the left and right, which in turn can lead to problems with binocular vision.

Near object distance

If, for example, your customer states a reading distance (NOD) of 30 cm in conjunction with an addition von +2.00 dioptres (the average value is 38 cm) then the inset should be slightly more nasal due to the slightly closer reading distance and the accommodation of the wearer. The inset on a conventional progressive lens would remain unchanged and, as a result, the near zone would not be fully exploited. This may cause aberrations that can restrict the field of vision.

Complexity of the calculation method

The ultramodern method used to calculate be 4ty+® VIP 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 μ 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+® VIP model range is based on this complex calculation method. It takes not only the form and position of the progressive lens into account, but also your customer‘s individual and habitual way of looking. Every surface of a be 4ty+® VIP model is unique, both in design and surface precision.

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