Snow Blindness: What It Is and How to Treat It​

Introduction to Snow Blindness

Winter is here. While you may be prepared for the cold and the fun outdoor activities that come with it, most overlook protective eyewear. For many people, the focus is on cold weather gear that makes winter activities safe.

If you are guilty of overlooking protective eyewear during winter, you may be at risk of suffering from snow blindness (or photokeratitis). During winter, the dry air coupled with cold wind and temperatures wreak havoc on the eyes. For instance, your eyes may become drier than usual.

If you reside in the Greater Toronto Area and want effective proactive eye care during this winter season, consider contacting optometrists at Kodak Lens Vision Centres to discuss how you can get maximum protection from snow blindness and related conditions. You can also book an eye exam to determine if the discomfort you are feeling is in fact snow blindness or dry eyes and learn the next steps you should take to ensure your recovery. 

What is Snow Blindness?

In the simplest terms, snow blindness or photokeratitis is the equivalent of a sunburn, but on your eyes. Snow blindness tends to affect two main parts of the eye i.e., the conjunctiva (the thin and clear membrane covering the white part of the eyes and inside the eyelids) and the cornea (the outer clear layer of the eyes) responsible for focusing light and enabling clear vision¹.

While the eyes (like the skin) have their own protective mechanisms against harmful UV rays, these measurements can be compromised by prolonged/intense exposure to UV rays, resulting in inflammation, discomfort and/or irritation.

Contrary to the term, snow blindness doesn’t actually cause blindness. However, the symptoms can be very severe.

Sunlight and Snow

To understand snow blindness in-depth, it’s important to discuss the relationship between sunlight and snow. When the sun strikes snow, the snow reflects both visible light and UV radiation, which can be damaging to the skin and eyes.

Fresh snow can reflect 50-88% of UV rays back towards you. This is way above the reflection by other natural surfaces like white sand (at 15 to 18%)². What’s more, uneven surfaces make the problem worse by causing multiple UV ray reflections, which increase overall UV exposure.

This explains why the UV glow in the snow is usually intense. Generally, a quick glance at the snow with your naked eyes won’t harm you, just like glancing at the sun for a millisecond won’t cause serious, long-term damage. However, your naked eyes are likely to water immediately from the resulting sensation.

Unless you are wearing a pair of shades that offer protection from UV light, you are bound to develop snow blindness even during overcast days.

What Causes Snow Blindness?

Snow blindness can be traced to a specific type of ultraviolet ray: UVA rays. The most harmful UV rays i.e., UVC rays, are filtered out naturally by the atmosphere. UVA and UVB rays penetrate, but most are absorbed by the atmosphere.

When exposed (depending on altitude, latitude, season, etc.), both types of rays are harmful to the skin and eyes. While UVB rays are largely responsible for sunburns, UVA rays are responsible for eye-related damage³. When they penetrate the eyes, they are known to cause burns on the conjunctiva and cornea, leading to photokeratitis or snow blindness.

Sunglasses offering over 99% UVA protection will significantly reduce snow blindness-related eye damage.

Snowblind Symptoms

So, what does snow blindness feel like? How is the eye condition exhibited? Here are the most common symptoms of snow blindness:

• Eye pain
• Watering eyes
• Eye swelling
• A headache
• Seeing halos around lights
• A gritty feeling in your eyes
• Redness in your eyeballs and eyelids
• Eyelid twitching
• Pain or light sensitivity when seeing bright lights
• Rarely, vision loss
• Blurred vision

Eye Damage Due to Sunlight

Overexposure to sunlight (ultraviolet radiation) can damage various parts of the eye. For instance, it can damage the Cornea and Conjunctiva, causing photokeratitis or snow blindness.

UV rays can damage parts of the eyes like the lens, causing eye conditions like cataracts⁴. Staring directly at the sun will damage the retina, causing permanent vision loss (solar retinopathy)⁵. UV overexposure on the eyelids can cause basal cell carcinoma, among other skin cancers of the eyelids⁶. 

You can protect your eyes from the above damage by wearing sunglasses that block UV radiation.

Is Snow Blindness Permanent?

No! Snow blindness, like typical sunburns, is generally temporary and heals on its own over several days. It won’t cause permanent damage. However, it can be worsened by actions like rubbing the eyes. Such movements can scratch or infect parts of the eye, resulting in long-term damage.

Risks of Snow Blindness

As mentioned, snow blindness will go away on its own. However, prolonged exposure to harmful UV rays outdoors without protective eyewear can eventually cause:

• Cataracts
• Growths on the eyelid
• Loss of vision
• Farsightedness

Snow Blindness Treatment

If you already have the condition, don’t worry! You can do the following:

• If you currently have contact lenses, take them out if you notice any symptoms of snow blindness and avoid wearing them for a while.
• Get indoors, in the shade, or generally away from the sun.
• You can use artificial tears (eye drops for lubricating dry eyes) to ease symptoms like eye dryness caused by snow blindness. A cold compress will ease symptoms like discomfort.
• Book a consultation with an optometrist to evaluate and provide better care.

Luckily, if you reside in Toronto or the Greater Toronto Area, you can head over to any one of seven Kodak Lens Vision Centre locations; Ajax, North York, Etobicoke, Riverdale, Rexdale, Scarborough, or Toronto and get proper care for snow blindness or dry eyes. 

Book an appointment with any of Kodak Lens Vision Centre’s experienced optometrists and discover more about snow blindness. You can also explore photochromic lenses, sports goggles, high-quality sunglasses and other eyewear capable of eliminating exposure to UV light. 

References

1. 2023, What is photokeratitis?, AAO.org:
2. 2021, Factors Affective UV radiation Levels, cancercouncil.com:
   
3. 2023, UV Radiation & Sun Exposure, epa.gov:
4. 2019, How to Protect Your Eyes From UV Damage, hopkinsmedicine.org:
5. 2017, Why You Shouldn’t Stare at the Sun, Healthline.com:
6. 2015, Eyelid Cancer, Cancer.net: