The Effects of UV Rays on Vision

Last Updated on February 9, 2024 by Josh Wilkerson

During the harsh, cold winter season, thoughts are weary, days are cloudy, and you were probably doing everything you could to keep yourself warm . But finally, the passing of few months led to warmer weather and before you know it, you are outside happy and free. Every spare moment, you are at your backyard in your tank top, shorts, and flip flops. You are so happy that winter is gone (for now) that you indulge yourself outside as much as you possibly can—bike rides, jogs, dog-walks, barbeques, basketball, swimming—you name it. Physical activity is good, but too much sun can become a concern. We’ve all heard of the damaging effects of UV radiation from the sun, such as sunburn and skin cancer, but did you consider how it affects eye health? We know—it’s hard to imagine that the bright yellow thing in the sky, which makes us feel good, can affect eye health and skin. Of course, sunglasses will help protect you against UV rays, if you have the right pair. However, it is only beneficial important for you to know what the sun has to offer the common risks and side effects of exposure to the sun, especially if you enjoy being outdoors.

Ultraviolet Radiation
UV rays are commonly referred to as “UV light”, however this is technically incorrect because UV rays cannot be seen. Did you ever think there are different types of UV radiation? There are three categories of UV rays. They all have different effects on the Earth and everything in it. Let’s zoom in to see what each of them are and how it affects eye health.

Categories of UV Rays

  • UV-C Rays
    These are the highest-energy UV rays which can potentially be the most harmful to your eyes and skin. Thank goodness, the atmosphere’s ozone layer blocks all UV-C rays. However, there is always catch. If there is a depletion of the ozone layer, then the UV-C rays have a way to reach the Earth’s surface and potentially cause health problems.
  • UV-B Rays
    These UV rays are slightly lower in energy compared to UV-C rays. UV-B rays are partially filtered by the ozone layer, but some still reach the Earth’s surface. UV-B rays, in low doses, stimulate the production of melanin (a skin pigment), causing the skin to darken, creating a suntan. However, if you’re exposed to this in higher doses, UV-B can cause sunburn and increase the risk of skin cancer. How rude, right? To make things worse, too much exposure to UV-B rays can lead to skin discoloration, wrinkles and other signs of premature aging of the skin. Who wants to look older—especially before their time?Skin is only one part of the equation when it comes to UV-B rays, but what about its effects on eye health? These UV rays are known to cause pingueculae and pterygia. Yes, the names of these conditions are hard to pronounce and not pleasant to have. These two conditions cause growths on the eye’s surface which can cause corneal problems as well as distorted vision.

    So what happens when you have high doses of UV-B rays during short periods of time? It can potentially cause photokeratitis, commonly known as “snow blindness.” This condition is a painful inflammation of the cornea which causes temporary vision loss usually lasting 24-48 hours. Snow blindness is greatest at high altitudes, but it can occur anywhere there is snow if you don’t protect your eyes with UV-blocking sunglasses.

What is Photokeratitis?
Photokeratitis is a painful eye condition that occurs when your eye is exposed to invisible rays of energy called ultraviolet (UV) rays, either from the sun or from a man-made source. Photokeratitis is like having a sunburned eye. This condition affects the thin surface layer of the cornea — the clear front window of the eye — and the conjunctiva, which is the cell layer covering the inside of the eyelids and the whites of the eye.

By now you are aware that photokeratitis is caused by damage to the eye from UV rays with sunlight being the main source. So how can this happen? Photokeratitis can be caused by sun reflection from sand, water, ice and snow. Do you remember the time you went skiing on a bright day and as you looked at the snow, the brightness hurt your eyes? If you stare too long, it can be damaging to your eyes. It can also happen if you stare at the sun, so don’t even bother trying we don’t recommend doing this, either. Does watching the solar eclipse excite you? It is just as exciting to us as it if for you. You would need a special device to see the solar eclipse. We strongly recommend to NEVER watch the solar eclipse without this device. Just a heads up, a solar eclipse can cause a burn to the retina, which is long lasting and more serious than temporary corneal damage.

You may not even realize you have photokeratitis. It can sneaks up on you like a sunburn on your skin, so you may not notice it until well after the damage has occurred. Do yourself a favor and make your eye health a priority, especially when you’re outdoors when there is the beaming sun in strong sunlight. Below are some symptoms:

  • Pain
  • Redness
  • Blurriness
  • Tearing
  • Gritty feeling
  • Swelling
  • Sensitivity to bright light
  • Headache
  • Seeing halos
  • Small pupils
  • Eyelid twitching
  • Rarely, temporary vision loss

We hope you never have to encounter this condition, but if you do, then make sure you remove your contact lenses (if you wear them) immediately. Get out of the sun and go into a dark room. For relief, you may try:

  • Placing a cold washcloth over your closed eyes
  • Using artificial tears eye drops
  • Taking certain pain relievers as recommended by your ophthalmologist
  • Using eye drop antibiotics, if your ophthalmologist recommends this
  • Avoid rubbing your eyes as you heal. Symptoms usually go away gradually in a day or two

Photokeratitis may be prevented by wearing eye protection that blocks UV radiation. This includes:

  • Sunglasses that block or absorb 99 percent and higher of UV rays
  • Snow goggles designed to block UV rays
  • Welding helmets

UV-A Rays
UV-A rays have lower energy in comparison to UV-B and UV-C rays. UV-A rays are known to reach the Earth’s surface 95% of the time. They are present during all daylight hours and can penetrate through clouds and glass. What happens when there’s too much exposure to this type of UV ray? There has been a link to certain types of cataracts and it may play role in macular degeneration.

In summary, UV-C rays are absorbed by the ozone layer and does not present any threat. The UV-A and UV-B can have adverse long and short-term effects on the eyes and vision. Man-Made UV Light?

We know everyone, especially women likes to get a golden tan. So when there is no sun, people go to man-made sources such as tanning lamps and tanning beds. This means that these are man-made sources of UV light. Remember, when exposed to UV light excessively, it is not only damaging to eye health, but skin as well.

HEV Radiation Effects on Eye Health
So far we have mentioned that UV rays are invisible and cannot be seen. But there is a blue light called high-energy visible radiation that has longer wavelengths and lower energy compared to UV rays. These rays are dangerous since they can penetrate deeply into the eye and cause retinal damage. According to a European study published in the Archives of Ophthalmology, HEV radiation when combined with low blood plasma levels of vitamin C is associated with the development of macular degeneration.

Risk Factors on Eye Health
You’ve already guessed it: If you’re spending lots of time outdoors, you know who you are. The more time spent outdoors, the greater the risk for eye health problems from UV radiation. Risks of eye damage from UV and HEV exposure change from day to day and depend on a number of factors, including:

  • Geographic Location. UV ray levels are greater in tropical areas near the earth’s equator. The farther you are from the equator, the smaller your risk.
  • Altitude. UV ray levels are greater at higher altitudes.
  • Time of Day. UV ray and HEV levels are greater when the sun is high in the sky, usually from 10 a.m. to 2 p.m.
  • Setting. UV ray and HEV levels are greater in wide open spaces, especially when highly reflective surfaces are present, like snow and sand. In fact, UV exposure can nearly double when UV rays are reflected from the snow. UV exposure is less likely in urban settings, where tall buildings shade the streets.
  • Medications. Certain medications, such as tetracycline, sulfa drugs, birth control pills, diuretics and tranquilizers, can increase your body’s sensitivity to UV and HEV radiation.

Cloudy Days
Just when you thought the clouds could block UV rays, it is the complete opposite. Your risk of UV exposure can be quite high even on hazy or overcast days. Remember that UV is invisible radiation, not visible light, and can penetrate clouds.

Sunglasses for UV Ray Protection
Shopping for sunglasses? In order to ensure proper protection, sunglasses should:

  • Block out 99 to 100 percent of both UV-A and UV-B radiation
  • Screen out 75 to 90 percent of visible light
  • Be perfectly matched in color and free of distortion and imperfection
  • Have lenses that are gray for proper color recognition

The lenses in sunglasses should be made from polycarbonate if you participate in potentially eye-hazardous work or sports. If you spend a lot of time outdoors in bright sunlight, wrap around frames can provide additional protection from the harmful solar radiation.