How To Deal With Snow Blindness (Photokeratitis)

Can your eyes get sunburned? Most of us have learned to be careful when going out in the sun; we cover every exposed inch of skin with SPF-30 sunblock (or higher) and take every reasonable precaution to avoid sunburned faces and limbs.

What many of us don’t realize, however, is that it is quite possible to acquire sunburn on our eyes—specifically, on our corneas and conjunctiva. This condition is known as photokeratitis, or “snow blindness,” and it results from allowing our eyes to be exposed to ultraviolet light for too long or too often.

What Causes Snow Blindness?

It is important to understand that direct sunlight is not the only—or even the most common—cause of photokeratitis. The reason this condition is commonly known as “snow blindness” is that it is easily caused by the reflection of sunlight off snow and ice, although reflections of sunlight off water or sand can be just as problematic.

Solar eclipses often cause outbreaks of photokeratitis increasing the number of visits to urgent care centers and eye doctor offices. While most of us are told from the time we are children never to look directly at a solar eclipse, some people are apparently unaware. Therefore the warning should be repeated here: never stare directly at the sun, even during an eclipse.

The tools used in some industrial occupations, such as welding (see below), can also generate enough UV light to injure the eye. Other man-made sources of UV light can be found in tanning beds or lamps.

While the number of tanning salons in the US has declined 30 percent in the last decade, 35 percent of American adults report having used them, putting themselves at increased risk for photokeratitis.

How Do I Know I Have Snow Blindness?

The symptoms of photokeratitis include:

• Intense eye pain
• Red,watery eyes
• Blurred vision
• Swelling
• Headache
• A gritty feeling, like a foreign body in the eye
• Extreme sensitivity to light (photophobia)
• Constricted pupils
• Possible eyelid twitching
• In some cases, temporary color changes in vision

The damage done by the sun or other UV light sources can also be cumulative, gradually reducing the visual acuity of people who spend too much time in the sun or who otherwise expose themselves to UV light on a regular basis.

The potential damage to your eyes from excessive sun exposure is not limited to snow blindness; other complications of UV exposure include various eye and eyelid cancers, pterygium, macular degeneration, and cataracts.

What Are the Risk Factors for Snow Blindness?

The most important risk factor for photokeratitis is lifestyle. Skiers and beach enthusiasts are prone to this condition, as are welders, among whom it is known as “arc eye.” The intense light generated by welding operations necessitates strong eye protection, including welding goggles and helmets.

Another important aspect of lifestyle as a risk factor for this condition is where you live; people who live at high altitudes are at greater risk because the thinner air provides less protection from ultraviolet radiation.

Eye color can also affect your susceptibility to snow blindness; people with lighter-colored eyes are more vulnerable to photokeratitis, as well as to certain types of melanoma that can also result from sun exposure. Because 54 percent of Americans have light-colored eyes, this is a significant public health issue.

Finally, nearly a third of American adults use medications that, unbeknownst to them, increase their sensitivity to sunlight—and their vulnerability to UV-ray damage. These drugs include:

• Antibiotics (doxycycline, sulfas, and ciprofloxacin)
• Antidepressants
• Nonsteroidal anti-inflammatories such as ibuprofen (the active ingredient in Advil and Motrin) and naproxen (the active ingredient in Aleve)
• Cholesterol medications (statins)
• Antihistamines
• Diuretics, AKA “water pills”
• Diabetic medications (glyburide and glipizide)
• Acne medications (Accutane)

How Is Snow Blindness Treated?

In most cases, if the damage is not too severe, photokeratitis will go away on its own. Treatment therefore focuses on reducing pain until the eyes have healed. Until medical attention can be obtained, however, it is important to try to minimize the damage. Get away from the sun, if possible, and put sunglasses on if you can get hold of a pair. Once you are out of the sun, you should seek medical attention as soon as possible.

While you are healing, do not rub your eyes. To soothe them, you can lie down and place a cold washcloth over your eyes. Your eye doctor may prescribe pain relievers or eye drops. In most cases the symptoms of snow blindness will abate within a couple of days.

What Steps Can I Take to Prevent Snow Blindness?

Always wear sunglasses outdoors year round, even on cloudy days. While the visible light may appear dim on a cloudy day, ultraviolet light can pass through the clouds. In the wintertime, it’s important to protect yourself not just when skiing or sledding, but even when shoveling snow or taking a walk.

Choose your sunglasses carefully—you should not go by how dark they appear to be, but by whether they block UV-A and UV-B radiation, which will be indicated by labeling that says, “100% UV protection” or “UV400.”

Wear a wide-brimmed hat if you’re going to the beach. If you are going skiing or snowboarding, wear snow goggles that are designed to block UV radiation. If your occupation requires you to use equipment that generates intense light, wear whatever safety gear is recommended. Most employers have a safety eyewear program for employees who work in potentially harmful environments.

For contact lens wearers, be aware that some popular brands of contacts are manufactured with excellent UV blocking material, but most are not. Even if you wear contact lenses with UV blocking, the protection is limited to your corneas and pupils, not the sensitive tissue of the conjunctiva or eyelids.