The perfect price: Sunglasses

Low: $20

High: $500

Perfect price: $70

Think twice the next time you start reaching for that $20 pair of non-prescription sunglasses at the drugstore. Be prepared to spend at least $70 for a quality product that has well-built frames and, most importantly, has lenses that will adequately protect your eyes from the sun. “Below that price, some sunglasses may fit the bill but a lot of them won’t,” says Dr. Ralph Chou, a vision science expert at the University Waterloo. Your work doesn’t just stop at price point, however. There are several factors you have to take into account before plunking down your money. Consider the following tips.

Lens type

Although Canada has no official standard for sunglass lenses, most products sold here are made in Europe and satisfy the American non-prescription sunglass lens standard: the Z80.3. This type of lens meets certain minimum levels of protection from UV radiation. As long as you see the Z80.3 compliance label on your lens, you can be assured you’re receiving adequate sun protection, says Dr. Chou.

Lens shape

Optical concerns may come into play if a lens is not properly shaped. Even an expensive pair of glasses can be set up with cheap lenses, warns Dr. Chou. He advises that anyone looking at non-prescription sunglasses hold the lenses up to the overhead lights in the store. All lenses will have a curved reflection, but look for any distortion of the reflections indicated by waves and other things that make it look uneven. “That can create problems in terms of comfortable vision,” says Dr. Chou.

Lens colour

Because most people use non-prescription sunglasses for activities like driving (where they have to see coloured traffic light signals), it’s critical to select a lens colour that is not going to impair your vision in any way, says Dr. Chou. Fail-safe lens colours that won’t do this are greyish-green, brown-tinted or grey. If you have a lens that is too dark, it may seem comfortable, but it will inhibit your visual perception and slow your reaction time, says Dr. Chou. “An acceptable pair of sunglasses for general use has a light transmission of 15% or greater.”

Frame

“The frame is as important in the sense that if it’s not very well made it’s not going to last,” says Dr. Chou. “If you’ve got a frame that feels chintzy and feels like it won’t hold up, it probably won’t.” Signs of quality frames can typically be determined by their finish, he says. Run your finger tip over the surface of the frame components—it should be smooth, with no rough spots or sharp edges that can irritate the skin. If the frame has nose pads or metal side arms you also want to make sure those are sturdy enough so that they can be adjusted for a proper fit. “The cheaper they are, the more flimsy they are,” says Dr. Chou, “and the less likely you are to make those adjustment and have them stick.”