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Sunglasses: UV Radiation & Your Eyes

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Filtering out sunlight that’s too bright isn’t the only reason to wear sunglasses. Sure, the idea of comfort against the blinding light of the outdoors is what spurs us toward the sunglasses rack. UV light is much more dangerous than discomfort from squinting. Optometrists recommend sunglasses for the safety from an invisible hazard, and UV protection on them is a must.

What is UV radiation?

Ultraviolet (UV) light is a part of the electromagnetic (EM) spectrum that you might remember from junior high science class. Many gadgets produce or harness EM waves, from radio to infrared, and from ultraviolet to x-rays. The thing to remember about EM radiation is that shorter wavelengths carry more energy! When it comes to your body’s cells, energy level matters.

Types of UV Light

UV light (i.e. radiation) can be grouped into three subtypes: UVA, UVB, and UVC. UVA and UVB light measure in wavelengths from 280 to 400 nanometers, while UVC wavelength can be as short as 100 nanometers. UVC is the most dangerous type. But the ozone layer, a part of the upper atmosphere, filters UVC light. It also protects us from the sun’s x-rays and rarer gamma rays.

Still, 95% of UVA and 5% of UVB light penetrates the atmosphere and reaches the surface. If you’ve ever wondered what the UV index on your weather app might be, it’s referring to the intensity of UVA/UVB light at ground level. Unfortunately, UVA and UVB light can penetrate cloud cover, and it can bounce off buildings, snow, water, rocks and more.

When it comes to human health, anything beyond the visible spectrum of light becomes hazardous to our health, for the most part. The exception is your skin’s production of vitamin D3 from UVB light. That and, depending on your point of view, UVA is what gives us a tan — which some find attractive. UVA and UVB light can each cause skin cancer, though, so you have to be careful!

The Effects of UV Radiation on Your Eyes

The World Health Organization estimates that 80% of lifetime UV damage to your eyes comes before the age of 18. Children’s outdoor play and their clearer ocular lenses might be factors. As we grow older, that’s when we might start to see effects.

Sunlight is a package deal. To bask in the visible light that makes it daytime, you’re going to get a dose of UVA and UVB radiation. UV radiation has a noticeable effect on your skin, including sunburn and a tan.

When it comes to your eyes, the damage usually becomes noticeable after it’s too late. When you get a sunburn, your body flushes skin cells with blood to promote healing. But your eyes don’t have that defence mechanism, so it’s hard to tell when you’ve received damage.

Behind your pupils is your ocular lens, a soft, clear, dome-shaped tissue that focuses images toward your retina, at the back of your eye. This type of tissue suffers a large portion of the UV radiation. Later in life, UV damage can speed the development of cataracts. Part of cataracts prevention involves a nutritious diet, but sunglasses are your first line of defence.

How Sunglasses Protect Your Eyes

A quality pair of sunglasses guards against the invisible hazard posed by UVA and UVB light. Sunglasses found at your optometrist’s office have been vetted for this vital quality. It’s crucial that you always look for a pair with a guarantee they filter 99-100% UVA and UVB light. In particular, that 5% of UVB that makes it to the earth’s surface doesn’t need long to hurt your eyes.

When Should You Wear Sunglasses?

With that rating, you can protect the cells making up your ocular lens tissues. Since you can’t know when you’ve received dangerous amounts of UV radiation, it’s best to wear them from dawn till dusk, whether it’s cloudy or not! Much of the UV radiation damage our eyes receive occurs in the early morning when your guard might be down, due to lower brightness. Moreover, many people take their sunglasses off when there’s cloud cover, which grants a false sense of security.

Features Your Sunglasses Need

That false sense of security resurfaces when buying sunglasses that aren’t rated to filter around 100% of UVA/UVB radiation. Sufficient UVA/UVB protection is the first thing to look for! But there are other factors you should keep in mind to complement UV protection.


Your sunglass lenses can come in different tints as well, offering distinct advantages. If your vision can be enhanced because of the tint, you won’t be as tempted to risk UV exposure. Choose between grey, brown, and green lenses based on your hobbies or preferences!

  • Grey: compensates most for high light sensitivity, also suitable for enhancing colours and contrast
  • Brown: grants precise colour representation, good for variable light conditions and provides high contrast for sports and other activities
  • Green: excellent for colour accuracy and contrast, and grants enhanced depth perception in direct sunlight as well as low-light

If you really wanted to, you could keep several pairs of sunglasses. Each pair could be rated for 100% UVA/UVB protection but with different tint levels. Your go-to sunglasses might be too dark for cloudy weather, but a pair with lighter tint could work. Also, a UV coating can be applied to regular eyeglasses without the tint. It’s just as effective at UV filtration as proper sunglasses.


Fit can be something to think about. Wraparound style sunglasses are ideal because they don’t let light in over the rim and around the sides if worn correctly. But a good pair of prescription sunglasses will offer a lot of protection from UV light, especially to the most sensitive parts of your eye. It’s essential to wear your glasses or sunglasses properly wherever you put them on.

Wear Sunglasses When in Doubt

Sunglasses are a surefire solution for protecting your eyes. UV light is an invisible hazard, and our eyes really have no way to let us know when they’re receiving damage, unlike our skin.

Our eyes can’t easily heal from this type of damage, either. If you ignore all warnings, you might find yourself requiring eye disease management someday. Your best bet is prevention. We can always set you up with a pair you’ll love, so you can enjoy the sunshine with fewer worries. While we’re not skin health experts, we do recommend sunscreen as well!

Written by Joey Postma

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