Photokeratitis describes damage to the eye due to ultraviolet (UV) ray exposure. It can cause pain and blurry vision. Using protective eyewear, such as sunglasses, can help to prevent photokeratitis.

Everyone experiences exposure to UV radiation from the sun, even though people cannot see or feel it. However, UV rays can cause tissue damage by exposing people to excess levels of radiation. People most often notice this as the redness and soreness of sunburn, but these effects can extend beyond the skin.

Sunburn of the eyes, or photokeratitis, is also possible if a person stares directly at the sun or takes in too many reflected rays from surfaces such as water, sand, ice, or snow.

However, the condition is treatable and easily preventable as long as a person takes the correct precautions.

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Photokeratitis is an eye condition that develops after a person has exposure to UV rays without using eye protection. The term “photo” refers to light and “keratitis” describes inflammation of the cornea.

It develops similarly to sunburn. In particular, photokeratitis damages cells on the clear surface of the eye (the cornea) and the layer underneath (the conjunctiva). This can cause cells in the conjunctiva to shed their outer layer, exposing the nerves and causing pain and inflammation.

Photokeratitis occurs due to direct or reflected exposure to UV rays. As such, most UV exposure to the eyes can occur from directly staring at the sun, or due to UV rays from the sun reflecting from sand, water, ice, or snow.

For example, staring at the sun during a solar eclipse without using suitable protective eyewear can result in damage to the eyes known as retinal burns, or solar retinopathy. This damage may lead to permanent blindness. However, more temporary photokeratitis can also result.

Snow blindness describes when a person develops photokeratitis in colder climates when UV rays reflect off snow. It is worth noting that snow can reflect as much as 80% of UV radiation.

There are also man-made sources of UV light that can damage the eyes, including tanning lamps, tanning beds, and arc welding. When photokeratitis occurs due to an arc welder, some people refer to it as arc eye or welder’s flash.

According to a 2018 review, factors that may affect the intensity of UV exposure include:

  • the height of the sun in the sky and the time of day, which is the most important factor
  • the season
  • the amount of ozone in the atmosphere
  • how reflective the ground is

Photokeratitis is temporary but uncomfortable. Its symptoms get worse the longer a person has exposure to UV rays, and they can develop shortly after exposure. Photokeratitis symptoms include:

  • blurred vision
  • halos appearing in the visual field
  • headaches
  • increased tearing
  • increased sensitivity to bright light
  • pain
  • redness
  • small pupils
  • swelling
  • the feeling of sand or grit in the eye when no foreign materials are present
  • vision loss, although this is rare and temporary

People sometimes experience color changes to vision as a result of photokeratitis, although this is rare.

Photokeratitis often resolves without treatment and should gradually go away within a day or two. Treatment usually involves relieving pain and discomfort while the eye tissue heals. Immediate measures for people with photokeratitis include the following:

  • removing any contact lenses and avoiding them until the eye fully heals
  • getting out of the sun where possible
  • entering the nearest dark room

Some home treatments and prescribed medications can help provide relief for keratitis while healing occurs, including:

  • putting a cold, damp washcloth over closed eyes
  • using over-the-counter eyedrops containing artificial tears
  • taking ophthalmologist-recommended pain relievers by mouth
  • taking antibiotic eye drops, such as erythromycin, if a doctor, such as an ophthalmologist, prescribes it

Photokeratitis is completely preventable if a person wears the right protection.

People at risk of recreational UV exposure, such as those who are mountain climbing or traveling in a hot climate, should choose sunglasses that block at least 99% of all UV rays in accordance with American National Standards Institute requirements. Snow goggles can also help block UV rays and prevent snow blindness.

When viewing a solar eclipse, people should only view it through specialized eclipse glasses or handheld solar viewers. Regular sunglasses are not dark enough to make looking directly at the sun safe. A person should also avoid looking at the sun through a camera lens, telescope, or binoculars.

Welders should wear the standard occupational protection for welding work. This typically includes a full face shield with adjustable shade levels.

Not everyone will need to consult a doctor about photokeratitis, as it heals without treatment within a couple of days.

However, people with ongoing eye pain or vision loss may benefit from a consultation. A doctor will ask about recent activities and carry out an eye exam. They can also prescribe pain relief to improve comfort during healing.

Photokeratitis is similar to sunburn of the eyes. Ultraviolet (UV) rays can trigger cell death in the cornea and conjunctiva, which may lead to eye pain and soreness. The best way to protect the eyes against photokeratitis is to wear eyewear that reduces exposure to UV rays.

For people in warmer, sunnier climates, UV-protective sunglasses can block most UV rays. For those in snowy environments, snow goggles can reduce the reflected UV rays. Welders can use full-face shields to reduce UV exposure in an occupational environment.

If photokeratitis does occur, it usually self-resolves in a few days. A cold compress, oral pain-relief medications, and artificial tears can improve comfort while the eyes recover.