What Are Transitions Lenses?
Transitions lenses are a brand-specific type of photochromic lenses. Other companies that produce contact lenses and glasses make transition lenses under headings such as reaction lenses, graduation lenses and Reactolite lenses. All these lens types use photochromic technology to assist user vision through a range of light conditions.-
Purpose
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Photochromic lenses are different from standard lenses as they develop tint when exposed to UV rays. This means users don't need a separate pair of prescription sunglasses, as the transition lenses will form a tint to shield their eyes on sunny days. This can be tiresome, especially if you are going from shop to shop on a hot summer's day and can't see price tags due to the tint on your sunglasses. Switching glasses is not only irritating, but can also increase the chance of a pair being left in a cafe or restaurant. Glasses that can rest on your face for the whole day are much less likely to go astray.
Light Adaptation
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Transitions lenses don't only produce a tint on glorious summer days. UV rays are present even on cloudy days and these rays can damage your eyes if experienced for prolonged periods. Transitions lenses produce a pale tint on overcast days, with the tint becoming darker as higher levels of sunlight occur. When indoors, Transitions lenses become clear again, meaning you can watch TV or read a book without the tint disturbing your vision.
Driving
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Transition lenses were formulated to take the hassle out of changing glasses for outdoor and indoor tasks. Transition lenses may not react, however, when driving a car. This is due to the fact that most windscreens come fitted with some UV protection in the glass. If the windscreen inhibits UV levels sufficiently, there may not be enough UV to activate the tint in the glasses. Many people who use Transitions lenses keep a cheap pair of sunglasses in the car due to this lack of reaction.
Comparison
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Transitions lenses can be purchased as standard plastic lenses or in polycarbonate form. The lenses usually take around 30 seconds to develop a tint once exposed to sunlight after a period indoors. Reactolite lenses are a rival brand that uses the same photochromatic technology. These lenses are not as quick to react, however, but they are more responsive when driving as they activate at lower levels of UV light.
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