What Are Rear Surface Progressive/Varifocal Lenses?

Nov 6, 2008

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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. Rear Surface Lens

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: Example of Rear Surface Lenses 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. Selecting Rear Surface Lenses 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

Comments

5 responses to “What Are Rear Surface Progressive/Varifocal Lenses?”

wendy freedman

March 12, 2009

Please can you advise me . i am in my early 40s adn was born severely amblyopic in my l eye. i HAVE ALWAYS NOT CONSIDERED IT A PROBLEM ANF QUALIFIED AS A DOCTOR AND HAD A FAMILY. 5 YEARS AGO FROM NOWHERE i DEVELOPED DENSE CATARACTS . i HAVE HAD BILATERAL IMPLANTS AND HAD MY SEEING EYE A LENS EXCHANGE AS THE FIRST LENS DID NOT WORK, THEN i HAD EXTENSIVE CORNEAL LASEK TO MY SEEING EYE AND RECENTLY A RADIAL KERATOTOMY. TIMES HAVE BEEN HARD AND OFTEN WITH VERY POOR SIGHT i CANNOT WORK NOW . i HAVE GONE THROUGH MANY TYPES OF VARIFOCALS ESSILOR ZEISS 360 DEGREE LENS AND SEIKO LENS MOST RECENTLY THE SURGEON HAS FINISHED WITH ME AND i CANNOT FIND A VARIFOCAL THAT IS BEST i STRUggle TO SEE WELL IN THE DISTANCE AND HAVE LOST A LINE OF VISION mT IMPLANT IS A TECNIS LENS FIXED FOR INTERMEDIATE VISION. WHAt would you recommend would rear surface lens help me who can hep me whenever I go for varifocals I have spent 1000s pounds over the years and operations I so need some impartial advice

Reply
SelectSpecs

March 13, 2009

Hi Wendy

Thank you for your inquiry, we are sorry to hear about your problems, this is very unfortunate, we would suggest speaking to your optician to confirm if these lenses will be suitable for you based on your Intra-ocular implants.

Rear Surface progressives is an exciting new technology which uses computer controlled lens designs, the progression is worked on the rear surface of the lens providing wider fields of view, this helps to reduce the “keyhole Effect” which can be found with traditional progressive lenses.

Kindly see here for full details: http://www.selectspecs.com/info/rear-surface-progressives

Kind Regards
SelectSpecs Team

Reply
Yaakov Ben Natan

August 30, 2009

How can I order glasses with Rear Surface Lenses?

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andy dawson

March 20, 2010

I wouldlike to order Freeform rear surface Varifocals but I am not sure whether i can also choose ultran-thin index lenses at the same time…and also what the advantage in doing so would be. Can you help?
many thanks!
Andy

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Martyn Cowley

October 11, 2012

I have worn varifocals for many years now but have had a great deal of difficulty getting a pair this year. The frame of my previous pair broke in January and I returned to the optician (a local independent) for new ones. The first pair was wrong – the left lens completely out of focus. They were remade and I accepted them but realised after some time that the focus of both lenses did not coincide – I had to turn my head slightly to bring the same object into focus with the left eye as had been in focus with the right. As my right eye is the dominant one I was seeing a sharp image with that and a blurred 'halo' from the left. I have put up with this for some months, but decided it was not ideal and went to a branch of a national opticians for new ones. The testing was thorough and efficient but the manufacture was deficient – the lenses were centred too low. The frame style did not allow sufficient adjustment to correct this, so they were remade with different measurements – or not, as the case was – the second set were exactly the same. A third attempt was better but still not correct, so I took a refund and went to a different national concern. I chose their 'top of the range' varifocal as this promised the widest fields of vision and would, I thought, alleviate the focus alignment issue. I was wrong. Even though the individual lenses provide correct vision, at the intermediate and reading distances the in-focus images do not coincide – to a worse degree than my original pair. The optometrist 're-spotted' the lens (with all the hi-tech kit used for determining the prescription I find it incredible that centreing is done by hand) by a millimetre or so and the left lens was remade. I went to collect the revised glasses today – better, but still not right. I will give them one more opportunity to correct them and if unsuccessful will demand another refund.
I find it amazing that three different opticians are incapable of making a pair of glasses that can focus both lenses on the same object. The small differences in centreing of just a millimetre or two seem to belie the 'wide zones' claim – is this purely marketing hype?

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