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People who wear eyeglasses permanently understand the inconvenience of carrying around both regular prescription eyeglasses and prescription sunglasses. Photochromic (Transitions) lenses offer the all-in-one solution of regular glasses transforming into sunglasses when exposed to UV rays. Here’s what you need to know.
When you wear eyeglasses full time, your glasses become part of your being - like a second skin. Half the time you forget that you’re wearing your eyeglasses and the reality hits when you step outside and the glare of the sun reminds you that you do not have appropriate UV or sun protection.
Sunglasses are an obvious option and with the stylish designs available it’s no wonder that so many choose to buy a pair of prescription eyeglasses in conjunction with a pair of prescription sunglasses. Still, having to remember to swap glasses and having to remember to actually carry both with you at all times can become tiresome and irritating.
In the late 1960s, Corning came along and introduced photochromic lenses into the eyeglasses industry; however, it was the brand, Transitions, in the 1990s that pushed this form of lenses into the market. Today, Transitions is the leading manufacturer of this type of lens and their branding success has led to the lenses being aptly referred to as "Transitions lenses."
What exactly are these lenses? How do they work? How do they benefit long term eyeglass wearers? Photochromic lenses include an all-in-one prescription eyeglasses and prescription sunglasses solution with special lenses manufactured with a special mix of chemicals which react with one another when exposed to ultraviolet (UV) rays.
Essentially, the lenses darken into sunglasses when outside and exposed to sunshine (aka ultraviolet rays); yet slowly return to being regular indoor eyeglasses as soon as the UV is removed. The amount of shade the lenses turn is dependent on the amount of UV light they come in contact with.
The general timeline is that they will respond to either the UV rays, or the absence of them, within one minute, and then gradually darken or fade over a course of fifteen minutes; however, the full visual effect is usually seen within five minutes. An important side note is that when outdoors, photochromic lenses will darken enough to protect the eyes against harmful UVA and UVB rays, but will not darken to the point of looking like true sunglasses.
An important note to keep in mind is that photochromic lenses do not respond to visible light - only to UV light. Therefore, there are times when, you are outdoors and yet, they will not darken - such as while driving. To compensate for this and ensure maximum optical protection, most photochromic lenses also contain anti-glare tints.
As a method for helping with certain medical conditions, photochromic lenses can be tinted to a specific color (most often red) to help patients to see when eye conditions have caused visual deterioration (as in the case of macular degeneration patients).
With advances in technology and manufacturing capabilities, photochromic lenses are now available in a wide range of materials, and are usually very lightweight -therefore glass is rarely used. Those needing multifocal glasses can also enjoy the benefits of photochromic lenses, along with those who wear standard vision-correcting prescription glasses.
In the end, there are clear advantages to this form of lens, though we also cannot blind ourselves to any disadvantaged. Advantageously, one needs only one pair of eyeglasses to perform three of the most important optical roles - providing clear sight; protecting against the sun’s harmful rays; and blocking against glares which can cause headaches, eye strain and car accidents.
The very small disadvantage is that they do not automatically transition to the state that you need them for and so, you will find yourself with semi-sunglasses for a few moments when you step inside; and regular eyeglasses for a few moments when you step into the sun.
Just a few last points: as it currently stands, one can buy glasses with photochromic lenses in shades of gray and brown. Advances in manufacturing have also ensured that aside from being suitable for multifocal glasses, as well as regular ones, they are available to fit into any frame of any style, color or lifestyle need. Convenience, protection, style and comfort - all in one frame!
Hillary Glaser is a social networking specialist and expert in cross-media promotion, currently working on promoting prescription eyeglasses. She is the Director of Marketing and Special Projects for GlassesUSA.com - the easiest way to buy glasses online, which now offers free shipping on all US orders with the code FreeShip10.
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