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Abstract

This article follows the evolution of multi-focal lenses through the latest innovations in progressive lens technology. Multi-focal technology begun much earlier than most imagine, yet gained its boost only in the recent two decades, for socio-economic reasons. What is the state-of-the-art progressive lens technology today? What’s next, and what is the future of this market?

The article argues that the future of eyeglasses lenses is in advanced Free Form technologies combining sophisticated software algorithms and robotics, bringing the complete lens design and manufacturing to the optical laboratory level. Single vision Semi-finished lens blanks turn into individually-unique lenses for the specific patient’s lifestyle. This future is already here with commercially-available technology.


An Early Beginning

Benjamin Franklin is credited for inventing the first pair of bifocals in the early 1784. According to the story, “He was getting old and was having trouble seeing both up-close and at a distance. Getting tired of switching between two types of glasses, he devised a way to have both types of lenses fit into the frame. The distance lens was placed at the top and the up-close lens was placed at the bottom.”

The early Bifocals

Use of eye care industry multi-focal correction lenses increased from 40% in the 80s of the last century to 53% of total correction lenses dispensed in USA in 2008 (Jobson Publication).

Bifocal lenses have two powers only: one for seeing at distance and the other for seeing up close or reading. Objects in between (such as computer screen or items on the grocery store shelf) often remain indistinct with bifocals.

Attempts were taken to compensate this shortcoming with tri-focal lenses which offer the wearer additional field of corrected vision. Yet, the Bifocal and tri-focal lenses are carry an inherent disadvantage and are uncomfortable due to the sharp transition between focal points. Moreover, in some cases the use can lead to quite a few unpleasant outcomes. One hazard is known as Computer Vision Syndrome (CVS), might result in from using a computer for extended periods. Bifocal wearers have to sit closer to the screen and tilt their heads back to see through the bottom part of the lens. This unnatural posture can lead to muscle strain, neck pain and other symptoms of CVS.

Natural Vision Correction

The idea of natural vision correction avoiding an "image jump" - progressive addition lenses (PAL) was first patented in 1907 by Own Aves (British Patent 15,735), but due to the impracticality and complexity this design was never commercialized. The Varilux lens was the first modern design of PAL. It was developed by Bernard Maitenaz, patented in 1953, and introduced by the Société des Lunetiers (that later became part of Essilor) in 1959.

The illustration of a progressive lens below shows the typical configuration of distance, intermediate and near zones

Early progressive lenses offered relatively crude designs creating regions of aberration away from the optic axis, yielding poor visual resolution (blur). Combining a collection of powers in a single surface resulted in geometric distortions to the visual field, increasing with addition of power. The early progressive-enthusiastic users accepted these disadvantages for a very simple reason: Progressive lenses gave them a "younger" look; Since bifocal and related designs are associated with 'old age', the lack of segments on the lens surface of a progressive lens appears more 'youthful' because lenses associated with younger wearers, as single vision lenses are free of segments or lines on the surface.

The motto those days was "The best progressive design". Market leaders attempted to develop pre-made designs to fit wide range of cases (e.g. Varilux Comfort). Yet, this "one size fits all" concept did not satisfy the growing market of aging young individuals.

Mid 1990s through 2006 – Quest for the ideal progressive lens

It is very much thanks to the maturing Baby Boomer generation that the decade following the mid 90s was a constant quest for the ideal progressive lens. The mid 1990s were the beginning of economical prosperity, which lasted through the first decade of the second millennium. Unlike their ancestors, Baby Boomers reaching their 40s and 50s had the financial stability to demand eyewear suited to contemporary lifestyle, supporting their office, leisure and sports activities. Ah and, yes. The eyewear must also be fashionable and “young” looking.

Industry giants were challenged by increasing consumer demand combining comfort with fashion. Smaller frame styles became fashionable and three piece rimless mounts and wrap around sport glasses complicated the task even more.

Introducing the Free Form Lenses

It was a small, unknown Israeli company Shamir, who first introduce the next revolutionary concept, turning away from the "ideal design” concept to the extreme opposite: Individually tailored lens for each patient, optimized for his/her condition, problem and lifestyle. The revolution materialized with the commercial implementation released to the market in 2001. It so happens that these pioneers came from outside the eye care field, combining mathematicians, software and robotic architects. Thinking “out-of-the-box” they have succeeded to implement cost-effective desktop-manufacturing technology enabling optical labs to produce high-quality individually-tailored lenses from plain single vision blanks.

Threatened by the new technology revolutionizing the market and consumers’ expectations, industry leaders were each forced to come up with a matching commercial response. This has indeed yielded a variety of branded “Free Form” implementations. Unfortunately, they all differ and lag behind the original Shamir technology for the mere fact that they bind the client laboratory to pre-manufactured blanks of that brand. A little disappointing, isn’t it? After all, it seems that during those years more efforts were placed into marketing campaigns rather than in research aimed to real freedom…

It is something to expect, that most of the eye care industry leaders weren’t too happy with the new emerging technology. The immediate commercial implication is freeing the laboratories from huge inventories of pre made semi finished lenses and thus dependence from industry leaders. Realizing this provides an explanation to their resulting solutions “overcoming” this problem by tying the user labs to their proprietary blanks. It is understandable. They are trying to hold the fort for as long as they can…

Conclusions

So what do we have so far?

1. We have a growing aging “young” consumer population demanding eyewear supporting combinations of activities and lifestyles unparalleled before.
2. We have a variety of desktop production solutions, which accommodate the consumers’ demand, yet are mostly driven by the giant lens manufacturers, and limited to pre-manufactured proprietary blanks.
3. We have witnessed the feasibility and availability of more freedom achieved with technology such as Shamir’s, that goes one step further and frees the lab from dependency on specific blanks and manufacturer.

Understanding similar scenarios in other industries in is inevitable to realize that technology-based commercial processes can be delayed but not stopped.

Dan Sadovsky
C.E.O K-Mars Optical

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