Sunglasses are now available in more styles, brands, materials and colours than ever before. Today’s sunglasses are both functional and fun. Sunglasses can be worn as a fashion accessory to compliment a ‘look’, give greater visual performance and comfort outdoors, and offer protection against the elements. Whatever reason you wear sunglasses, all sunglasses should improve your visibility against bright light and glare, and protect your eyes against ultraviolet (UV) radiation.
The Importance of UV Protection
The most common misconception about sunglasses is that the darker the lens, the higher the UV protection. However, the darkness of the lens has little to do with protecting your eyes from potentially harmful UV radiation. In fact, dark lenses without UV protection can do more harm because the pupils dilate in very dim conditions, allowing more UV rays to enter the eye. The cornea, lens and retina are all vulnerable to UV rays and research shows that continuous exposure to UV light contributes to the development of cataracts or macular degeneration and can cause a form of corneal sunburn called photokeratitis. Consequently, it is important that the sunglasses we wear protect us against UV rays. Proper UV absorption is either an integral part of the lens material or must be added as a coating on the lens.
Inexpensive sunglasses are available from retail stores and street-side vendors, especially in the summer. Knowing the level of protection or the optical quality of these sunglasses is not always possible at the point of purchase. Your eyecare professional will ensure you are getting the proper sun product that meets your specific needs.
Glare is a phenomenon in which reflections from horizontal surfaces such as water, roads, snow, and sand create polarized light to be reflected into the atmosphere. This polarized glare washes out detail and colour, and makes viewing difficult and uncomfortable. Similarly, hazy conditions also cause glare, because light bounces off dust particles in the air. Glare causes impaired vision outdoors as well as distorting colour and depth perception that can lead to eyestrain. Glare can be painful and dangerously distracting while driving or playing sports. The most effective way to eliminate glare is by wearing polarized sunglass lenses. The addition of the polarized material to a sunglass lens blocks reflections that cause glare. Reducing glare provides comfortable viewing, increases visual clarity, depth and colour perception. Polarized lenses also provide 100 percent UV protection and are ideally suited for anyone who is going to spend time outdoors. Special lens treatments such as mirrored coatings and back surface anti-reflection coatings are also effective to reduce glare and reflect bright light.
Shades and Tints
The varieties of lens tints available today are staggering and can be confusing. The importance of colour choice depends on the specific ‘sun’ need. The traditional greys, browns and greens provide specific benefits such as, colour neutrality, colour contrast and eye comfort. Amber, yellow, orange and red filters can increase depth perception and colour contrast by absorbing blue and green wavelengths. These colours are beneficial for low vision conditions like cataracts, macular degeneration, and glaucoma. The pinks, blues, and violets are fashion colours that project a fashion trend, mood or are just fun to wear. Some manufacturers provide tints that are specific to sports activities such as golf and tennis. These lenses increase contrast and enhance colours such as the green of the golf course or the yellow of a tennis ball. Check with your eyecare professional to ensure you are wearing the right tint and colour density for your needs.
Eighty percent of our lifetime UV exposure occurs by the time we are 18, so an early start to wearing sunglasses is ideal. However, UV exposure is cumulative over time, so it is never too late to start practicing good sun protection habits!