Sport sunglasses: Controlling light, enhancing performance
Sports sunglasses may give an edge to athletes at all levels, including amateur "weekend warriors" who always are looking for ways to improve their performance in the sports they love.
However, in their rush to try the latest and greatest gear, such as new tennis rackets or shoes, many sports enthusiasts overlook a key factor in optimising their sports performance — their vision.
Sport sunglasses manage light for better performance
Vision is, of course, about how we process light to create the images we see.
All light, including outdoor sunlight, is composed of a variety of electromagnetic rays of different colours, determined by their wavelengths.
Rays of violet, blue, green, yellow, orange and red light each have a specific wavelength, depending on colour. When combined, these rays create white light.
When transmittance of certain wavelengths into the eye is selectively reduced, tinted performance sunglasses can diminish glare and enhance contrast sensitivity.
With this ability to see with greater speed, accuracy, clarity and comfort, the athlete may have a key advantage over competitors.
This extra edge of better vision with sports sunglasses can manifest itself in different ways, depending on the sport. In golf, for example, tinted lenses can enhance contrast between light and dark patterns of the grass on greens, enabling you to "read" greens better for more accurate putting.
Other examples:
In tennis, softball and cricket, tinted lenses can help you see the rotation of the ball more clearly so you can make better contact with your racket or bat.
For biking, sunglasses with the appropriate lenses may help you see better down the road or trail for a safer ride, especially when travelling downhill at high speeds.
How to choose a sunglass tint
To some degree, selecting a tint is a matter of personal preference. However, certain tints offer advantages for specific visual tasks and environments.
If 100 percent accuracy in colour perception is key, a neutral grey tint is the best choice.
For most athletes, contrast enhancement is the most desired feature for activities such as viewing a ball against the sky, a fish under the water, upcoming moguls on a ski slope or for a variety of other sports-specific tasks. To enhance contrast, brown and copper-coloured tints are often best.
Depending on lighting conditions, yellow (for low-light and overcast conditions), amber, orange and even red tints also are good choices for contrast enhancement.
Lens tints and UV protection
If you're into sports, you probably spend more time in the sun than the average person.
If so, it’s important to make sure your sunglasses offer 100 percent UV protection. Lifelong overexposure to ultraviolet (UV) rays has been linked to the development of cataracts later in life.
The amount of UV protection offered by sunglass lenses is determined by the lens material and coatings or additives applied to the lens. Therefore, the colour and darkness of a sunglass tint are not reliable indicators of its ability to shield your eyes from ultraviolet (UV) radiation.
It's possible for a pale yellow lens to offer 100 percent UV protection and for a dark grey lens, depending on its quality, to offer little or no protection.
A good choice for sports sunglasses is polycarbonate lenses. These lenses are lightweight and shatter-resistant, and they block 100 percent of the sun's harmful UV rays without extra additives or coatings.
Recent research also suggests it's a good idea if you spend prolonged periods outdoors to wear sunglasses that block high energy visible (HEV) radiation from the sun — sometimes called "blue light" — in addition to UV rays. A good quality grey tint will filter up to 75% of the blue wavelengths while a Transitions lens will filter up to 85%. Some research indicates long-term exposure to HEV light, for some at risk individuals, may be a factor that contributes to macular degeneration.
Consult your optometrist to choose sports sunglasses that block 100 percent UV and filter blue light.
Supercharge tints with other lens features
Although tints alone can improve your sports vision significantly by changing the quantity and quality of light entering the eye, you also may want to consider adding these performance-enhancing features to your sports sunglasses:
Photochromic lenses
These tints lighten and darken automatically in changing light conditions, making them very beneficial for outdoor activities lasting several hours. As weather conditions change or the sun begins to set, photochromic lenses will adjust to allow the optimum amount of light to enter your eyes for good vision.
Polarised sunglasses
These lenses contain a special filter that selectively blocks light reflecting from horizontal surfaces, eliminating "hot spots" of glare. Polarised lenses are especially helpful in blocking glare from light reflecting off water, sand, snow and concrete.
Anti-reflection coating
Applying an AR coating to the back surface of your sports sunglasses will eliminate ghosting from sunlight reflecting off this surface when the sun is behind you. To reduce the likelihood of this even further, choose a wrap-style frame design so your lenses fit closer to your face.
Mirror coatings
For very bright conditions, such as hiking, skiing or glacier walking at high altitudes, consider adding a mirror coating to the front surface of your sports sunglasses. These coatings can block an additional 10 percent to 60 percent of visible light for greater comfort in high reflection full-sun environments.
How many sport sunglasses do you need?
It’s wise to have different sport sunglasses for different lighting conditions.
A yellow or amber colour may be best for overcast conditions, while a medium or dark brown lens may work better for sunny days.
Or you may prefer different tint colours for different activities.
Some sports eye-wear companies offer sunglasses with interchangeable lenses in different colours for greater versatility. Consult your optometrist for details.
Page published on Wednesday, 18 March 2020
