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When it comes to choosing sunglasses, the options are endless, which can be confusing without some important background information. Not all lenses are equal in terms of UV and blue light protection. The optical quality of the lens, the level of protection and the longevity of such protection vary greatly. Here are a few helpful tips:
- Visible light and UV light: The light spectrum is categorized by wavelength. If the light is in the visible spectrum, the wavelengths will determine its color. If it is in the UV range, the wavelengths determine its UV category (A, B or C).
- Blue wavelength light: Blue wavelength light can damage the retina, leading to AMD and blurring of vision.
- Types of glare: Direct glare is the bright light that comes from the sun above and its reflection below. Reflected glare is produced by flat, smooth and shiny surfaces, like a car windshield, the surface of a lake or puddles on the road. Bounce-back glare reaches you from the side and from behind.
The difference between a high-quality and a low-quality pair of sunglasses is determined by their UV protection and by how well they filter blue light. The gold standard in sunglasses for UV protection has until recently been UV 400, which protects against UV categories A, B and C. We now know that visible blue light also has damaging effects on the eyes, so optimal sun protection includes a selective blue filter. The once-popular “Blue Blocker” lens blocked all blue light rays, but it also changed the quality of the colors seen through the glasses. Newer lenses allow you to see colors normally while still absorbing the damaging energy of blue light.
Polarized Sunglasses: The best way to see clearly and distortion free is to have a pair of polarized prescription sunglasses. These will eliminate 100% of UV light, filter blue light, reduce glare and (unlike photochromic lenses) stay dark in your car when you are driving.
- The color, or tint, of a sunglasses lens does not affect the quality of its UV and blue light protection. In fact, you can get a clear UV 400 coating on your lenses. Cheaply made UV 400 sunglasses have a spray-on coating that will wear off with cleaning, giving you a false sense of security, and not all brands of lenses have blue light filters. A high-quality pair of sunglasses will filter blue light as well as UV light.
- A mirror on the front of your lenses will reflect most of the direct glare, essentially “squinting” so you don’t have to.
- A polarized filter eliminates reflected glare from the road, water, windshields and other flat, shiny surfaces. With polarized lenses, you can see below the water’s surface, so they are great for fishing.
- A back surface antireflective coating prevents light from bouncing off the back of the lens and into your eyes. This feature reduces glare.
- A photochromic lens adjusts to lighting conditions, getting darker as the light gets brighter. It is activated by UV rays, so it will not get as dark when you are inside a car as it does when you are outside.
- Excellent-quality plastic lenses will be impact-resistant, lightweight and treated with an anti-scratch coating. They will have high-quality optics, giving you sharper vision.
- Glass lenses are heavier and more resistant to scratching, and provide crisp optics. Because they are not impact-resistant and may shatter, they are not well-suited to sports use.
- You can choose the color of the tint of your sunglasses depending on your visual needs, how you intend to use your sunglasses and your personal preference. Brown tints increase contrast; gray tints do not alter color perception.
Pro Tip: Specialized tints are available for different sports and activities. You can get lenses that maximize your vision for tennis, golf, hunting and fishing, to name a few.
- When choosing the frame for your sunglasses, the most important thing to consider is fit. The frame should fit close to your eyes and face to reduce the entry of bounce-back glare, and it must be big enough to provide appropriate coverage and protection for your eyes.
- Most quality sunglasses are available with your prescription, so you don’t have to put up with wearing one pair of glasses on top of another.
- Clip-on sunglasses are available for most prescription glasses. Although these are an acceptable compromise, they add to the weight of your glasses, causing them to slip down your nose. There will also be internal reflection between the two sets of lenses, which decreases the quality of your vision. With frequent use, the clip may cause paint to chip off your frame.
- If you choose a clip-on or a photochromic lens, you should be aware that light will still reach your eyes from around the frame. This is because regular eyeglasses are usually smaller and flatter than sunglasses, and do not fit as close to your face.
Ask an Expert: Because there are so many options available, you will find it helpful to consult an expert when you are choosing sunglasses. Do some research ahead of time so you have a good sense of your preferences, then ask your optician or optometrist to help you find the sunglasses that will be best suited to your needs.