Carl Zeiss Vision’s new PhotoFusion lens becomes fully clear in only five to 10 minutes.

As with many products, the quality of lens features like progressive addition lens (PAL) design, digital surfacing, and anti-reflective (AR) treatments have improved dramatically since their introduction. With these changes has come increased market share: as performance gets better, more people buy the feature or product. Carl Zeiss Vision saw an opportunity for similar advancements in photochromics, which have been around for decades but are worn by fewer than 20% of eyeglass wearers. Its response was PhotoFusion, a new photochromic technology.

To assess the public’s attitude toward photochromic lenses, Carl Zeiss conducted a multi-national survey. Of the 5,800 eyeglass wearers surveyed in the study, 40% reported an interest in photochromic lenses, twice the percentage who actually buy them. What was holding the other 20% back from making the purchase? The main reason was performance, especially tinting and fade-back speeds. Carl Zeiss figured that if it could create a self-tinting (its term for photochromic) lens that worked better, more people would buy it.

The most significant advance is PhotoFusion’s clearing speed—how fast the lenses go from their darkened state to clear. According to independent tests conducted by COLTS Laboratories, PhotoFusion lenses fade and darken up to 20% faster than previous photochromic lenses by Zeiss.*

FIRST UP Carl Zeiss Vision has a long history with self-tinting lenses. One of its predecessor companies, American Optical, invented the first plastic photochromic technology in 1983. The lenses had the problems of current photochromics: changing speed was very slow, the swing between dark and light states was far less than it is today, and the lenses were completely ineffective after a couple of years. American Optical later went on to sell this patent to the company that became Transitions Optical.

Self-tinting lenses are notorious for wearing out. Over time, chromophores (the organic molecules that make photochromics work) decay and become less effective so the photochromic “swing” (the difference between light and dark states) is not what it once was. What’s more, plastic lenses can discolor and eventually have a faint yellow hue.

According to Carl Zeiss, the chromophores used in PhotoFusion lenses have been shown to retain more color stability than competitor’s lenses. After two years, the activation rate is almost the same as it was when the lenses were new. In testing, PhotoFusion shows less degradation in photochromic performance than previous photochromic lenses offered by Zeiss.

Reaction to temperatures has always been a challenge for photochromics. Cold makes them darker while heat makes them clearer. This means that on hot, sunny days (exactly when dark lenses are most needed), the lenses are struggling to darken. Carl Zeiss states that the patented PhotoFusion molecules have excellent color stability, offering exceptional color consistency between the darkened and faded states in all materials.

Gray and brown PhotoFusion is available in free-form lenses across the Zeiss, SOLA, AO, and VSP Reveal brands, and also in Zeiss GT2 and GT2 Short PALs. The price point is similar to the leading photochromic brand.

Carl Zeiss will continue to carry Transitions® lenses in all of its styles since it knows that some Carl Zeiss lens wearers trust Transitions and want to stick with that product. With PhotoFusion, they hope to boost the fitting of photochromics.
*Average performance based on material, temperature, and light.

Kate Jacobs is an optician at the optical shop at Scheie Eye Institute at the University of Pennsylvania.


Carl Zeiss Vision Inc.
800-358-8258 •


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