IF form follows function, then KBco has a winner with Wrap SolutionsTM polarized lenses. They solve the optical problems associated with placing steeply wrapped sunglass lenses in a frame while providing wearers with fashionable prescription sunwear. Their wrapped form functions well when Rxed.
Steeply Curved Optics
Steeply curved lenses pose special challenges to lens designers. Compared to typical flatter Rx lenses, they have a significant curvature that causes incident light rays to create more aberrations.
This means that the optical performance of steeply curved lenses depends on the neutralization of unwanted cylinder power and prism induced by face form (wrap), pantoscopic tilt, and power correction from the change in vertex distance. These issues are exactly what Wrap Solutions lenses correct.
Wrap Solutions lenses use an 8.25D nominal base curve for all prescriptions. However each Single Vision Wrap lens has a numerical aspheric identifier such as 8.1, 8.2, 8.3, 8.4, 8.5, or 8.6, which indicates a specific level of asphericity needed for a given prescription. The correct aspherically compensated option is chosen based on the lens power, patient's fitting height, monocular pupillary distance (PD), and frame data supplied.
Compensating the Lens
KBco's Wrap Solutions can be used in any frame that requires steeper optics. The optical compensation needed is easily calculated by using KBco's AccuCalc Rx-calculating software on the company's Web site.
The operator simply fills in the boxes on the form and prints two job tickets, one for the lab and the other for the patient's file. Because the Rx is re-calculated, the patient's monocular PD and fitting height must be taken. KBco encourages eyecare professionals to check with their lab before the customer leaves to be certain that the job is Rxable.
Even though Wrap Solutions lenses compensate for factors such as wrap, pantoscopic tilt, and vertex distance, no special surfacing equipment is needed. This means fast turnaround time and reduced costs for the lab and the ECP, which lead to higher customer satisfaction and positive word of mouth.
The benefits of these lenses go beyond their wrap capabilities and aberration correction. They also feature polarization in KBco True Grey, KBco Grey-C and KBco Brown-C, and are only available in polycarbonate to reduce thickness and weight while providing superior impact resistance. All lenses also have KBco's proprietary Super WearGardTM HC16 Hardcoat, which has a Bayer anti-scratch test reading of 16 (glass is 13).
Wrap Solutions lenses come in aspheric single vision Single Vision WrapTM and KBco's EOS WrapTM progressive addition lens design. Powers range from -6.00D to +4.00D total power in single vision and -4.50D to +2.50D total power in progressive.
Wrap Solutions single vision lenses incorporate 5mm of decentration into the blank, while the EOS has 3mm. Accompanied by a large 83mm lens blank, this decentration makes these lenses suitable for just about any oversized sunglass frame on the market.
Wrapped sunwear styles are all the rage these days. The only thing holding the sunwear Rx market back is the availability of properly designed lenses. KBco"s Wrap Solutions provides the solution.
Donn McCarthy is Optical Laboratory Manager at Optical Expressions in Wheaton, IL.
WHERE TO FIND IT
The Polarized Lens Company