I’ve been hearing about transitions lenses. What are they?
Studies have found that people of all ages can benefit from protecting their eyes from the sun. Those people who don’t need glasses to see can buy non-prescription sunglasses. However, people who wear glasses and need sun protection cannot, and they have a couple of options. The first is getting a clip-on that is placed over the lenses in the spectacles. The newer frames have clip-ons that are the same size, shape and colour as the frame beneath, so it looks like a sunglass when the clip-on is attached.
The second choice is getting a separate pair of prescription sunglasses. These lenses are permanently dark and have the same prescription as your regular glasses. The third choice is getting a photochromic (photochromatic) lens. Photochromic lenses change from light to dark depending on the amount of ultraviolet light they are exposed to. Early photochromics were glass lenses, but today, you can get them in a variety of materials. Transitions is simply the brand name of a plastic photochromic lens. Some other brand names are Photogray (glass), SunSensors, Colormatic. The lens material is made with special dyes which are activated when exposed to UV (ultraviolet) rays from the sunlight. The amount of tinting of the lens depends on the amount of UV hitting the lens, so you can have a range of darkness available. As the sunlight decreases, the lenses fade back to clear. This adjustment ( transition) from light to dark happens so smoothly that you are unaware of it.
Are transitions the best choice for me?
Transitions lenses block 100% of eye damaging UVA and UVB rays, as well as pure sunglasses. They reduce the discomfort of glare and provide automatic protection regardless of the atmospheric conditions (cloudy, overcast, sunny). They are ideal for people who spend a lot of time outdoors as they change automatically as opposed to putting away your clear glasses and bringing out a pair of sunglasses, or attaching a clip-on to your frame. However, remember that the UV light has to hit the lens before it will darken. If you need the sun protection primarily when driving, these lenses are not as effective since photochromic lenses won’t darken behind the windshield because the glass blocks out the UV rays that cause the lenses to change colour.)
What colours can I get,
and which is best?
Most photochromic lenses come in grey and brown. Both are equally effective, and purely for cosmetic reasons, dispensers tend to match the colour of the frame with the lenses. Both colours, whether in the clear or darkened state, block 100% of eye-damaging UV rays constantly.
I wear bifocals; can I still
get photochromic lenses?
Yes, these lenses come in different materials: glass, plastic, polycarbonate, ultrathin; and different designs: single vision, bifocal, trifocal, progressive. Consult your optometrist to select the best option for your particular need.
