Photokeratitis (Ultraviolet Keratitis): Causes, Symptoms, And Treatment

Did you know that your eyes could get sunburned? Photokeratitis, also known as ultraviolet keratitis, is a painful, but thankfully temporary, eye condition brought about by exposure to ultraviolet rays, the source of which is usually the sun. Just as sunburn affects the skin, photokeratitis affects the thin top layer of the cornea and the conjunctiva, which is the cell layer that covers the whites of the eye and the inside of the eyelids.

What Causes Photokeratitis?

The sun emits UV-A, UV-B and UV-C rays. UV-C is absorbed by the ozone layer so it does not harm us; however, the other two pass through and can cause both short and long-term damage to the eyes.¹ While the cornea of the eye blocks quite a bit of UV-B radiation, UV-A radiation can go really deep, easily penetrating the full thickness of the cornea. The damage can be either because of direct sunlight or because of sunlight reflected by ice, snow, water, or even sand. Staring at the sun directly, such as during a solar eclipse, can also cause eye damage.^2
3 If you enjoy the outdoors and activities such as hiking, swimming, or mountain climbing, your risk of photokeratitis increases. And light-colored eyes tend to be more photosensitive.⁴

Ultraviolet Radiation Can Hit Even On Cloudy Days

When the sun’s rays hit your eyes, your body’s natural reaction is to resist penetration. Your pupils constrict, your eyelids close, and you may even squint. However, these mechanisms are activated by bright, visible light and not by UV radiation. And, unfortunately, UV radiation may be quite high even on a cloudy day. So if you are outdoors skiing, snowmobiling, or mountain climbing, make it a point to wear your UV-protective sunglasses even if the sky is overcast.⁵

Snow Blindness: A Common Type Of Photokeratitis

Snow blindness or arc eye is an extreme but common type of photokeratitis and is caused by UV rays reflected off snow and ice. The condition is common near the South and North Poles and in mountain regions where the air is thinner, thus offering less protection from UV rays. Snow blindness may have other symptoms such as freezing of the cornea’s surface and severe drying of the corneal surface because of extremely dry air.⁶

Man-Made Sources Of UV Light Can Cause Photokeratitis

Extended exposure to man-made sources of UV light such as lasers, lamps used for tanning, welding equipment, mercury vapor lamps, photographic flood lamps, lightning, halogen desk lamps, metal halide bulbs, and carbon arcs can cause photokeratitis.^{7 8} Using a photocopy machine for long hours with the lid open has also been known to cause photokeratitis.⁹ Even UV lamps used in nightclubs have been associated with it.¹⁰

Symptoms Of Photokeratitis

If you suffer from photokeratitis, you may have:

• Pain or redness in the eyes
• A gritty feeling in the eyes
• A burning sensation
• Blurred vision
• Headaches
• Swelling in the eyes and/or lids
• Sensitivity to light
• Twitching of the eyelids
• Temporary loss of vision
• Halos and glares around lights

The symptoms may last 6 to 24 hours. They usually disappear within 48 hours.¹¹

If your eyes are subjected to repeated or intense exposure to UV radiation, photokeratitis may make an appearance after a latent period that can last anywhere between 30 minutes and 12 hours. The length of this period varies depending on the severity of the exposure and the eye pain and discomfort may set in much later. The complete absence of symptoms during this period is attributed to the dramatic drop in corneal sensitivity.¹²

Preventing Photokeratitis

Here are some tips to protect your eyes from UV rays when you go outdoors.

Stay In The Shade

If possible, stay in the shade when you are outdoors. Of course, in addition to that, you need to wear sunglasses, a hat, and protective clothes too.¹³

Use A Hat

Wear a wide-brimmed hat or visor when you go outdoors. The brim should preferably shade your face, ears, as well as the back of your neck. Straw hats are not the best choice since they allow sunlight in through the holes. Use a cap made of tightly woven fabric, such as canvas, for the best protection from UV rays. A darker colored hat may be a better option. A baseball cap works well if you make sure your ears and back of your neck are covered by some clothing.¹⁴

Use Eye-Protective Equipment At Work

Use proper eye protective equipment if you are exposed to UV radiation on the job. Anti-reflective coatings do what they are supposed to do but tests show that they do not protect your eyes from UV rays. In fact, even if the source of UV radiation is behind you, it can reflect off your glasses and impact your eyes. Only eyewear with a high wrap frame and high base curve lenses can prevent UV radiation from reaching the eye.¹⁵

Wear Effective Sunglasses

Just as you use sunblock for your skin before stepping out, make it a point to wear sunglasses before going into the sun. Do remember that even glare from snow, water, or sand can cause burns to the eyes, even when it’s cloudy or overcast. Wear your UV-blocking sunglasses if you are out in the snow, climbing mountains, trekking in desert sands, or getting tanned under a lamp. You may also need snow goggles to fight the snow–sun combination if you are skiing or out during harsh winters.

Choose sunglasses or goggles which absorb or absorb 99–100 percent of UV rays for optimal protection. Use wrap-around sunglasses or glasses with side panels if you plan to be outdoors for long. Sunglasses also protect the tender skin around your eyes.¹⁶

Buying The Right Kind Of Sunglasses

Before you splurge on a pair of fancy sunglasses, here are a few tips to keep in mind.

• Check whether the sunglasses are certified as 100 percent UV-blocking.
• Opt for oversized/wrap around styles – bigger is better where UV protection is concerned.
• Darker lenses do not necessarily provide UV protection.
• Pricey sunglasses are not necessarily UV-protective. Check for certification before you buy.¹⁷

First Aid For Photokeratitis

Once you are affected by photokeratitis,

• Go indoors immediately and stay for a while in a darkened room.
• Remove contact lenses, if any.
• Do not rub your eyes.
• Place a cold compress over your closed eyes.
• Keep your eyes moistened with artificial tears.
• Wear sunglasses indoors as well since your eyes may be extra sensitive to sunlight for a while.
• Talk to your ophthalmologist and take an over-the-counter non-steroidal anti-inflammatory pain reliever if necessary.
• You could also use a recommended antibiotic eye drops or try a reliable home remedy.

If you experience loss of vision or your discomfort lasts longer than 2 days, seek medical help.¹⁸

Soothing Home Remedies For Photokeratitis

Raw Potato

Place thin slices of raw potato over your eyes to reduce inflammation and soothe the eyes. A poultice made of scraped potato may also be equally effective.¹⁹

Plantain Leaves

Place fresh, green plantain leaves on the eyelids to relieve soreness and reduce inflammation. Fresh plantain leaves have antibiotic properties.²⁰

Cool Compress

Place a cool compress of lavender or hyssop tea on top of each closed eyelid for relief from pain.²¹