Dear Dr. Mo: How to be sure my sunglasses protect my eyes well from UV light? Is the price tag sufficient as guidance?
Dear reader: Your question is well timed and important and wherever we go, even when the skies are overcast with clouds, our skin and eyes are constantly exposed to UV light – invisible to us, but potentially damaging nonetheless.
Choosing the right protection becomes an integrative part of a healthy lifestyle.
The two forms of UV (Ultra Violet) light that affect our health are UVA and UVB. There’s also UVC, which can be extremely damaging but our atmosphere’s ozone layer filters it out completely so it does not figure in our review here.
UVA is responsible for skin tanning and aging and UVB is linked to sunburn and skin cancer; a large portion of UVB is also absorbed by the ozone layer.
UV light also affects eye health and darker lenses may not necessarily provide better protection from it. In fact, a dark lens with poor or no UV protection can do just the opposite – it can damage the eye by allowing more UV rays into it.
To avoid this peril, you can look for the label, which states the level of protection, a pair of sunglasses offers. These labels are made according to guidelines for UV protection created by the ANSI – American National Standards Institute.
Just the other day, I’d bought a pair of inexpensive sunglasses (for 3$ on sale in H&M) but they had a label attached to it, where it clearly stated that these glasses offered appropriate UV protection.
So, before buying sunglasses, look at the ANSI label and you won’t make a mistake; unless you’re buying some Chinese knock offs, then, all bets are off.
Lenses are generally categorized as follows:
Cosmetic lenses: Lightly tinted lenses, good for daily wear, which block 70% of UVB rays, 20% of UVA, and 60% of visible light. The 3$ pair I’d just bought would likely fall into this category.
General-purpose lenses: Medium to dark lenses, fine for most outdoor recreation – block 95% of UVB, 60% of UVA, and 60% to 90% of visible light. Most sunglasses would fall into this category.
Special purpose lenses: Very dark lenses with powerful UV filters, designed for very bright conditions such as on beaches and ski slopes. These lenses block up to 99% of UVB, 60% of UVA, and 97% of visible light.
Other quirks lenses may have are polarization of light, which is in my experience very good for driving conditions, antireflection coating, which tends to get dirty more easily and cleaning isn’t as straightforward, antifogging etc. but UV protection remains the most important element you should look for.
Eyes are not just windows into our soul but more importantly serve as our windows into the world around us and we should keep them in good shape.
Enjoy the summer.
Yours in health,