By Ronda Addy While keeping us warm, the sun is also responsible for the UV rays that can damage our skin and eyes. Of the three types of UV rays, UVA, UVB and UVC, UVB rays are the most dangerous to the eyes, making the wearing of sunglasses imperative. Even on overcast days, UV rays can damage the eyes. It is time to buy some sunglasses, but with all the different kinds to choose from, how do you know which is right for you? Sunglasses come with various types of lenses. Some of these include:
• Blue-blocker lenses, which are amber and block blue light. This style of lens is popular among skiers, pilots and hunters.
• Gradient lenses, which are tinted from the top down, making them a good choice for driving. Double-gradient lenses are tinted from the bottom up, making the top and bottom darker and the middle clearer. They are not a good choice for driving because they make the dashboard hard to see.
• High-contrast lenses, which are orange and yellow, resulting in a distortion of colors and making them unsuitable for driving. The contrast filtering aids in depth perception.
• Mirrored lenses, which limit the amount of light entering the eyes.
• Photochromic lenses, which adjust the darkness level according to the amount of UV light they are exposed to.
• Polarized lenses, which reduce the light coming from reflective surfaces. They can also filter diffused light scattered by the atmosphere. 
• Prescription lenses, which are prescribed by an optometrist to go along with your eyeglasses. Prescription lenses are available that can make the transition from dark to light when moving from outdoors to indoors.
• Scratch-resistant lenses, which are more durable than untreated lenses. Scratch-resistant lenses come in plastic and polycarbonate.
• Ultra-violet lenses, which meet the standards established for UV protection-60% UVA and 70% UVB. Check the label for the sunglasses’ UV protection level and shoot for a pair with 98% or better protection. For athletes, sunglasses with brown, non-polarized lenses are ideal because they let in more light, allowing the eyes to focus on the ball. However, there are some lenses that are better suited to some sports than others. Here is a brief list:
• Cycling and biking- High-contrast lenses are the best choice because they allow more light transmission while blocking all glare.
• Fishing, boating and sailing-Polarized lenses are the best choice for any type of water activity. 
• Golf-High-contrast lenses in cinnamon or gold are the best choice.
• Motorcycling-Polarized lenses are the best choice. If you plan on riding for long periods in the direct sun, mirrored lenses will work well.
• Running-Blue-blocker lenses are the best choice, although high-contrast lenses can be used. For running on cloudy days, light-colored lenses in citrus or lemon will work well. For running on sunny days, brown or gray lenses will work well.
• Tennis-Lenses that mute the whole spectrum except those in the optic yellow range are the best choice, allowing players to pick up the tennis ball quicker.
• Volleyball and softball-High-contrast lenses are the best choice for cloudy days, while brown lenses with a mirror coating are the best choice for sunny days. When selecting sunglasses, you should consider the shape of your face. Here are a list of some facial shapes and the best frames for them:
• Diamond-shaped faces look best in frames that add width above the cheekbone. Oval frames make a good choice.
• Oval faces are the easiest to fit because the face is symmetrical. The frame chosen should be proportionate to the face.
• Rectangularshaped faces look best in large, round frames, which add width to the face.
• Round faces look best in frames with angular lines that add definition to and sharpen the face. Rectangular frames make a good choice.
• Square faces look best in round frames that are not as wide as the widest part of the face.
• Triangular-shaped faces look best in frames that add width to the eyes and distract from the chin. The Food and Drug Administration requires all sunglasses to be impact resistant. Anyone involved in sports will want sunglasses with ultra-impact resistant polycarbonate lenses. Keep in mind that expensive doesn’t necessarily mean the best. It is possible to get a good pair of sunglasses for a decent price as long as they provide adequate UV protection and don’t cause distortions.

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