A Brief History of Progressive/Varifocal Lenses
The first commercially available Progressive (Varifocal) lens now referred to as the Varilux 1 was introduced by Essel (now called Essilor) in the early 1960’s. There have been considerable improvements in both design and production technology since, and today there are many different designs of progressive lens available in different materials such as glass, polycarbonate and plastic.
But wait… What are Progressive/Varifocal Lenses?
Progressive lenses are a true Multifocal lens which will deliver a seamless progression of distance, intermediate and reading powers to achieve all round comfortable viewing distances, as opposed to Bifocal lenses, which can only provide distance and reading visions with a visible dividing line. With progressive lenses, you can look up to see clearly across the room and into the distance. You can also look ahead to view your computer in the intermediate zone and drop your gaze downward to read and do fine work comfortably.
So What Are Rear Surface Progressive Lenses?
Rear Surface progressives is an exciting new technology which enables us to fully customise the progressive lens designs for each and every wearer, delivering consistent, perfect vision regardless of prescription and frame selection, comparative to the limitations of traditional lens manufacturing which can only be tailored for a broad category of wearers.
Here Comes the Science Bit…
This Rear Surface technique originates by deciding on an ideal or target optical performance for the lens design for the given prescription. The actual optical performance can then be determined using computer ray tracing and lens-eye modeling. Finally complex state-of-the-art computer generated algorithms map out the surface of the lens to achieve an optimized optical performance by minimizing the differences between the target optical performance of the design and the actual optical performance. The image below is a representation of a lens, which is normally circular before being cut into the appropriate shape for the selected frame.
What Are The Benefits of Rear Surface Lenses to the Wearer?
Fortunately, the individualized approach to Rear Surface Free-Form Lens Manufacturing ensures that every wearer enjoys the clearest distance, intermediate, and near viewing zones, eliminating the happy medium approach of traditional progressive/varifocal lens manufacturing, regardless of prescription or frame selection. Free-Form optimized prescription’s will ensure the widest fields of vision in comparison to traditional progressive/varifocal lens manufacturing, as much as 50% larger viewing zones will be achieved with a Rear Surface progressive, this is illustrated in the picture below: Thanks to its soft power profile, improved lens asymmetry and variable lens, the adaptation to Rear Surface Progressive Lenses are made easier compared to traditional lens manufacturing. One of our customers – David from Kent said: –
“I had never worn varifocals myself before but my wife does and she had always had trouble adjusting to new prescriptions. I thought I’d give the Rear Surface lenses a try and was amazed how quickly I adjusted to the new prescription. I wear my new glasses all the time now.”
Free-form rear surface progressive lenses are about to revolutionize the eyewear industry as they will give clearer, wider fields of vision. SelectSpecs.com are proud to be one of the first retailers to provide such a lens. What is more, we can offer these lenses with standard, Photo-chromic, Polarized, Super Thin 1.6 index, Ultra Super Thin 1.67 index lenses and UltraX Super Thin 1.74 lenses so why not see for yourself! If you want to try out this new Rear Surface technology yourself, when ordering your new glasses or re-glazing your own, select the option Rear Surface Varifocals/MultiFocals/Progressives under the Lens Types selection when entering your prescription on a Bifocal or Varifocal compatible frame. For more information, try our own help page What are Rear Surface Progressives? or for more general information on Progressive/Varifocal lenses, try this link to All About Vision. And don’t forget to check our extensive Help section on www.selectspecs.com