Non-prescription sunglasses: What to know before buying
Everybody loves wearing sunglasses — and most people wear non-prescription sunglasses.
Non-prescription sunglasses (also called "plano" sunglasses) are sunglasses that contain no lens powers to correct vision problems. As their name suggests, you do not need a prescription from an optometrist to purchase non-prescription sunglasses.
And non-prescription sunglasses are sold everywhere — from optometry practices to high-end boutiques and even petrol stations. Prices can range from extremely affordable to extravagantly expensive, depending on features, materials, and whether they are generic sunglasses or designer sunglasses.
Choices of non-prescription sunglass frames and lenses are nearly limitless.
Nonprescription sunglasses when you need vision correction
Many people who have short-sightedness, long-sightedness, or astigmatism choose to correct their vision with contact lenses and wear non-prescription sunglasses with their contacts.
The alternative is to wear prescription sunglasses rather than contact lenses and non-prescription sunglasses.
If you need vision correction and you find a pair of non-prescription sunglasses you really like, there's a good chance your optometrist can replace the plano lenses with prescription lenses of the same colour.
Another option is to have LASIK or other vision surgery to correct your refractive error and then wear non-prescription sunglasses without contact lenses.
No matter where you choose to buy non-prescription sunglasses, it's important to purchase only sunglasses that block 100 percent of the sun's harmful ultraviolet (UV) rays.
Over-exposure to UV rays can lead to serious eye problems over time, including sun damage to the front surface of the eye (conjunctiva), cataracts, and even certain cancers.
The amount of UV protection non-prescription sunglasses provides has nothing to do with the colour or density (darkness) of the lenses. UV radiation is invisible and is not significantly impacted by lens tints. It's the lens material and coatings on sunglass lenses that block UV rays.
Good-quality non-prescription sunglasses will have the Australian and New Zealand sunglass standards tag attached, this shows the level of UV protection the sunglasses provide. You can also look for the Cancer Council Australia or Cancer Society New Zealand logo as a guide that you're purchasing the right sort of sunglasses.
If your sunglasses don't provide sufficient protection, your optometrist often can order new lenses that will provide 100 percent UV protection.
For even greater comfort when wearing non-prescription sunglasses, look for styles that feature anti-reflection coating on the back surface of the lenses. This will eliminate ghost images from light reflecting off the back of the lenses when the sun is behind you.
Another option is to purchase non-prescription sunglasses with photochromic lenses that are clear indoors and automatically darken outdoors in sunlight. These lenses typically are available only at optical stores. Ask an optometrist to show you a demo of these sun-activated tinted lenses.
And if you want the best protection from glare caused by reflections off shiny surfaces, (think wet roads or at beach), purchase non-prescription sunglasses with polarised lenses. These lenses have a special filter in the lens material that eliminates the extremely bright reflections of light from water, car windscreens, snow etc.).
Polarised lenses reduce eye strain outdoors and are especially beneficial for seeing beneath the surface of water when sailing or fishing.