We know that the risk of cataracts is tripled by long-term exposure to the sun's UV (ultraviolet) rays. Protecting the eyes with sunglasses that block 100 percent of the sun's UV radiation is the best defence. Exposure of the unprotected eye to UV rays can also result in keratitis, a temporary loss of vision coupled with a burning sensation that results from inflammation of the cornea. A secondary solar threat the sun's heat, can dry out the eyes, cause eye fatigue and perhaps accelerate the negative effects of UV exposure.
In bright sun, aim to block out 75 to 90 percent of visible light, or 35 to 50 percent on dull days. The best color to choose for all-around use is neutral gray because it doesn't distort colour. Almost all quality sunglasses produced today offer essential protection against ultraviolet (UVA and UVB) radiation. Some lens materials have a built-in ability to absorb U/V light, but most protection is added in the form of lens coatings.
There is a reason wraparound-type frames and lenses are preferred by cyclists. Wraparounds assist with peripheral vision, and also help keep drying wind off the eyes while allowing enough air circulation to prevent fogging of the lenses. We also recommend polycarbonate lenses as they are virtually unbreakable.
So there you have it, wear sunglasses! There are plenty of good options for cyclists and all reputable brands will tick the boxes for you.