Summertime means lots of sun. While most sunglasses offer protection from the sun’s harmful effects, what kind of light is most dangerous and what kind of protection do you need?
Sunglasses Block UV Light
Ultraviolet light from the sun is linked to causing cataracts, eye growths and some cancers. Protecting your eyes from UV light is essential and you should always look for sunglasses which block ultraviolet light.
UVB light is considered to be more harmful to the eyes and skin compared to UVA light.
We recommend sunglasses that block 99% or 100 % OF ALL UV LIGHT. Some brands will claim “UV absorption up t0 400 nm” which is the same as blocking 100% UV light.
Sunglasses | Plastic Versus Glass
Both plastic and glass lenses can block ultra violet light. The lenses need to be treated specifically to block ultraviolet light and it is important to look for the label stating the blockage of UV light.
Neither is better than the other with respect to block UV light, but plastic lenses are usually lighter than their glass counterparts and are less likely to shatter.
Polycarbonate plastic sunglasses offer added strength and are tougher than regular plastic lenses, but they tend to scratch more easily. You might consider adding a scratch resistant coating.
Light polarization has nothing to do with blocking UV light. Polarized lenses decrease reflected glare from reflective surfaces such as windows, water (lake, stream, ocean), etc. Polarized lenses are often treated to offer UV protection.
Make sure to inquire if your polarized lenses also block UV light.
The degree of darkness does not relate to UV protection. Dark and light lenses transmit UV light equally. A medium colored lens is preferable for day to day wear, but make sure it has been specifically treated to block UV light.
Self Darkening Lenses and Blue Blocking
Neither inherently block UV light.
Self darkening (called photochromic lenses) lens automatically get darker with increased light and lighten in lower light. Blue blocking lenses are usually amber in color, do not necessarily block UV light, and make your surroundings appear yellow or orange. These are very popular for outdoors as they make distant objects more distinct.
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