Along the coast of Great Britain Sunlight breaks through the clouds after a brief thunderstorm, and a rainbow appears.


Did You Know…

…that Molecules Can Make Swapping Your Glasses a Thing of the Past?

Overcast skies in the morning, fluorescent lights at the office, bright sunlight in the afternoon, and subdued lighting in a restaurant in the evening – The lighting situation and general conditions experienced by our eyes change many times in the course of the day. The result is that you keep taking off your glasses, sometimes putting on sunglasses, which – if they they are corrective at all – rarely have the proper prescription. The consequence: unnecessary eyestrain. New, rapidly self-tinting lenses from ZEISS combine prescription power with effective light protection, thereby making swapping glasses superfluous for many situations.

The idea of developing one pair of glasses for all situations and lighting conditions is something that has occupied optical specialists for a long time now. Back in the 1960s, chemists Stanley Donald Stookey and William Armistead invented the first photochromic eyeglass lenses that react to UV radiation. Since then, a lot of improvements have been made to the quality and performance of self-tinting lenses. The reaction speed of the latest lenses is quick enough to enable comfortable vision in all lighting conditions. Within a few seconds, the lenses darken in bright sunlight to just ten percent light transmission, quickly clearing up again for cloud cover or indoor lighting. Photoactive color molecules regulate this process. When these molecules are exposed to UV radiation, they expand and cause the eyeglass lens to darken. The stronger the UV radiation, the darker the lens becomes, and vice-versa. In other words, the glasses themselves adapt to changing lighting conditions, putting an end to the tiresome need to keep switching glasses.

31 May 2011