Photokeratitis: Causes, Symptoms, Diagnosis, and Treatment

Published on December 15th, 2023

Updated on September 12th, 2024

Photokeratitis is defined as an eye condition that causes pain, as a result of ultraviolet ray exposure. Symptoms of photokeratitis include eye pain, redness, blurry vision, swelling, teary eyes, light sensitivity and a gritty sensation in the eye. The primary cause of photokeratitis is UV rays from the sun and other sources such as reflected sunlight from snow, water, ice, sand or cement. UV ray exposure may also come from tanning beds, laser light and from arc welding according to the Cleveland Clinic. You may be more at risk of developing keratitis if you frequently spend time outdoors doing activities such as hiking, swimming or skiing, use tanning beds often or reside in places with increased exposure to UV rays. Snow blindness, also known as arc eye, is a form of photokeratitis that can occur when snow or ice reflect UV rays.

What is Photokeratitis?

Photokeratitis is an eye condition that can cause damage to the corneal epithelial cells which can cause different levels of discomfort or pain and can develop as a consequence of ultraviolet radiation exposure. The effects of photokeratitis may be similar to the effects of a “sunburn” in which it is a burn that implicates regions of the eye as opposed to the skin according to the Cleveland Clinic.

What Does Photokeratitis Look Like?

Photokeratitis may look like an individual with red, watery eyes. Individuals with photokeratitis may also have the possible need to squint or close their eyes frequently as a result of increased sensitivity to light. The image below demonstrates what an individual with photokeratitis may look like, which can typically include red eyes.

Photokeratitis affected eyes showing signs of redness in the sclera.

What is the Medical Term For Photokeratitis?

There is no other medical term for photokeratitis, as photokeratitis is the medical term that refers to this condition. However, photokeratitis may also be commonly referred to as snow blindness or arc eye.

Is Photokeratitis the Same as Arc Eyes?

Yes and no, photokeratitis is not necessarily the same as arc eyes. Arc eyes is a form of keratitis that is caused by ultraviolet ray exposure from a welding machine. However, it is common to refer to arc eyes just as photokeratitis.

How Common is Photokeratitis?

Photokeratitis can be common, especially in countries with an increased risk of ultraviolet light exposure such as in Australia and New Zealand. However, there may not be an established number of cases. According to the Cancer Council, Australia is recorded as one of the countries with the highest UV index and highest rates of skin cancer due to its close location to the equator.

How Does Photokeratitis Differ From Keratitis?

Photokeratitis does not differ from keratitis because photokeratitis is a type of keratitis. Keratitis is characterised as corneal inflammation or infection as a result of causes such as bacteria, viruses or injuries in the eye. Photokeratitis is corneal damage from UV exposure.

What Age Does Photokeratitis Usually Appear?

Photokeratitis can affect individuals across different age groups. Photokeratitis can affect anyone who is frequently exposed to ultraviolet rays such as kids who are at school during peak radiation levels according to the Cancer Council.

Is It Possible For Kids to Develop Photokeratitis?

Yes, it is possible for kids to develop photokeratitis. Kids may be more vulnerable to ultraviolet rays damaging the cells in their eyes than adults according to the Optometrists Network. A child’s lens may allow 70% more UV rays to pass through the retina than an adult's according to the Optometrists Network.

What are the Causes of Photokeratitis?

The causes of photokeratitis are UV radiation, tanning equipment, mercury vapour and halogen lamps, arc welding, sun glare off water, snow and ice. The causes of photokeratitis are listed below.

UV Radiation: UV radiation may contribute to developing photokeratitis as it can easily penetrate through the lens of the eye and lead to damage.
Tanning Equipment: Tanning equipment may contribute to the risk of developing photokeratitis as it is another source of UV radiation.
Mercury Vapour and Halogen Lamps: Mercury vapour lights can be a cause of photokeratitis as they can emit UV radiation.
Arc Welding: Arc welding can produce UV radiation, increasing exposure to the welder and possibly those in the same environment.
Sun Glare off Water, Snow, Sand, and Ice: Sun glare off water, snow and ice may also contribute to the increased risk of photokeratitis as UV radiation can be reflected in the sun glare.

1. UV Radiation

UV radiation may be the primary cause of developing photokeratitis as UV radiation is able to penetrate the tissues of the eye leading to several different eye problems. UV light can lead to photokeratitis as it can harm the epithelial cells in the cornea. The cornea is the eye's outermost layer and functions as protection for the structures inside the eye according to Science Direct. The cornea epithelium functions as a protective layer against the external environment, and infectious debris and maintains the transparency of the cornea.

2. Tanning Equipment

Tanning equipment such as tanning beds and tanning booths may be a cause for photokeratitis as they can increase exposure to UV radiation. Tanning beds can contribute to UV exposure as they emit the same harmful radiation as sunlight according to the National Health Service. The extent of harm from tanning equipment can depend on the UV strength, frequency and duration of use and skin type.

3. Mercury Vapour and Halogen Lamps

Mercury vapour and halogen lamps are other sources of UV radiation that may lead to photokeratitis. Mercury vapour and halogen lamps are common lights used for streets, in stadiums and in school gyms as they are efficient for lighting large spaces, long-lasting and bright. However, UV radiation can be emitted if the outer tube is damaged or broken and continues to produce light without that shield according to the U.S Food and Drug Administration.

4. Arc Welding

Arc welding can expose the welder and possibly others in the same environment to UV radiation as it can produce the full spectrum range of UVR. Due to the short distance between the arc machine and the welder, there is an increased risk of ocular damage according to Anthony J Dixon and Brian F Dixon in their paper published in The Medical Journal of Australia.

5. Sun Glare Off Water, Snow, Sand, and Ice

Sun glare off water, snow, sand and ice may also factor as a cause for photokeratitis as UV radiation can be reflected when sun glare is reflected off certain surfaces. UV radiation may be scattered in different levels according to the different surfaces. According to the World Health Organisation, around 80% of UV radiation can be reflected off snow, 15% from dry beach sand and 25% from sea foam.

Illustration showing different causes of photokeratitis.

What are the Symptoms of Photokeratitis?

The symptoms of photokeratitis are pain in the eye, redness in the eyes, blurry vision, tearing eyes, gritty eyes, eye swelling, sensitivity to bright light, headache, seeing halos, small pupils, eyelid twitching and temporary vision loss. The symptoms of photokeratitis are listed below.

Pain in the Eye: Pain in the eye can occur when you develop keratitis due to the damage of the epithelial cells.
Redness in the Eyes: Redness in the eyes can occur as a result of damage to the cells on the surface of the eyes.
Blurry Vision: Blurry vision can also be caused by photokeratitis as the sun’s UV light can lead to temporary damage to the cells in the eye.
Tearing Eye: Tearing eye can develop as a consequence of photokeratitis and can typically occur along with redness and blurry vision due to UV light damage.
Gritty Eyes: Gritty eyes may be a common symptom of photokeratitis as the sunburn effect on the eyes can leave them dry and as a result gritty.
Eye Swelling: Eye swelling may arise from photokeratitis in response to the injury.
Sensitivity to Bright Light: Sensitivity to bright light may take place as the injury can leave the eyes tender or extra sensitive.
Headache: Headaches may be induced by photokeratitis and are characterised as pain occurring in the head.
Seeing Halos: Seeing halos can be a symptom of photokeratitis as the UV light damage may affect how the cornea refracts light.
Small Pupils: Small pupils also known as constricted pupils may occur due to the injury caused by UV light.
Eyelid Twitching: Eyelid twitching can ensue during photokeratitis and is defined as muscle spasms in the eyelid.
Temporary Vision Loss (Rarely): Temporary vision loss may develop in response to the damage.

1. Pain in the Eye

Pain in the eye can occur as a symptom of photokeratitis as UV radiation can cause damage to the corneal epithelium. Pain or discomfort may occur in the eye when the cornea’s epithelial cells are damaged as they help to protect the delicate structures of the eye according to the Nature Journal. Eye pain from keratitis can range from mild irritation to severe pain according to the College of Optometrists. You must seek medical attention from your local doctor or optometrist if you are experiencing eye pain.

2. Redness in the Eyes

Redness in the eyes can develop along with eye pain in response to UV light damage. Eye redness typically occurs when the blood vessels in the eye open to increase blood flow and trigger the healing process in the affected region. Red eyes are a common symptom in several other eye problems, therefore, it is important to see an optometrist to have your condition professionally diagnosed.

3. Blurry Vision

Blurry vision can ensue when experiencing photokeratitis as UV light can damage the cornea along with other regions of the eye. Blurry vision may occur due to the damage possibly affecting the cornea’s ability to bend light as it enters. Blurred vision is typically characterised as sight that is unclear and lacks sharpness, making it difficult to distinguish people and objects.

4. Tearing Eye

Tearing eyes can take place in response to the UV light harming the eyes as a way to wash the eyes and eliminate the cause of injury or irritation. Teary eyes may occur due to the sunburn effect on the eyes potentially leaving them overly dry and irritated, therefore, triggering the production of more tears.

5. Gritty Eyes

Gritty eyes may be a common symptom of photokeratitis and are defined as the rough or scratchy sensation in the eyes. Gritty eyes can commonly occur along with dry eyes, therefore, it may be helpful to have an optometrist prescribe artificial tear eye drops to restore moisture. Adequate moisture in the eyes may alleviate the gritty sensation along with excessive dryness. It is important to address symptoms such as gritty eyes with suitable treatment to prevent any further ocular issues.

6. Eye Swelling

Eye swelling may occur as a result of photokeratitis as part of the body’s natural reaction to injury. Swelling in the eye can take place when injury, infection or irritants get into the eye as a means of protection. Swollen eyes are characterised by the puffy appearance of the eyes and can commonly occur as a symptom of other eye problems and can typically take 24 to 48 hours to go down.

7. Sensitivity to Bright Light

Sensitivity to bright light can be a possible symptom of photokeratitis as the sunlight that penetrates the eye may affect the cornea. Bright light sensitivity may develop during photokeratitis due to exposed and damaged corneal nerves, affecting the cornea’s ability to process light according to the American Academy of Ophthalmology. Light sensitivity is often described as the need to squint or close your eyes when exposed to light.

8. Headache

Headaches can be a common symptom of photokeratitis as it may cause the eyes to overexert effort while processing so much light. Headaches can commonly stem from eye problems often due to overuse or when the eye muscles contract for too long. You may be able to distinguish if your headaches are caused by an eye problem when you remove the triggers that may be causing eye strain such as long exposure to sunlight or other sources of light.

9. Seeing Halos

Seeing halos can be a possible occurrence during photokeratitis as the UV light entering the eye can cause damage to the cornea. The cornea is responsible for bending light, therefore, you may experience seeing halos around lights, as a consequence of corneal damage from UV radiation according to the Optometrists Network. This symptom may be more noticeable when driving at night and typically appears around streetlights or other cars’ headlights.

10. Small Pupils

Small pupils, also referred to as constricted pupils, can develop from photokeratitis and can be described as pinpoint-sized pupils. The pupils naturally widen in low light conditions to allow more light in or shrink to reduce how much light can enter in bright conditions according to Medical News Today. Small pupils should be examined by an optometrist as it can be an indication of other eye problems that will need suitable treatment. However, it is always safe to see your optometrist when you notice any changes to your eyes or vision.

11. Eyelid Twitching

Eyelid twitching may ensue as a result of photokeratitis and is defined as muscle spasms in the eyelid. Eyelid twitching can last up to a week or longer depending on the severity of your condition. According to Health Direct, eyelid twitching may be reduced by getting more sleep, avoiding bright lights, using prescribed eye drops to increase moisture and avoiding caffeine. However, you must see an optometrist for eyelid twitching as they will be able to address the underlying issue of photokeratitis.

12. Temporary Vision Loss (Rarely)

Temporary vision loss may develop as a symptom of photokeratitis. When the eyes become inflamed from UV light damage, this can reduce the visual acuity of the eyes. However, vision loss from photokeratitis is considered rare and can depend on the severity of your condition. If you experience sudden vision loss, it is important to promptly seek medical attention either from your local doctor or an optometrist.

How Long Does Photokeratitis Last?

Photokeratitis lasts from a few hours to a couple of days. According to the American Academy of Ophthalmology, the corneal epithelium may heal within the time frame of 24-72 hours.

How is Photokeratitis Diagnosed?

Photokeratitis is diagnosed through an eye test conducted by an optometrist. The optometrist may first ask about the activities that may have caused your symptoms, conduct a full eye test and use fluorescein dye to identify UV damage.

Optometrist conducting an anterior slit lamp examination.

How Long Does it Take to Diagnose Photokeratitis?

It may take 20-30 minutes to diagnose photokeratitis. Eye tests at Oscar Wylee can take 20-30 minutes, however, this can also depend on other factors such as pre-existing eye conditions and age.

Do Optometrists Diagnose Photokeratitis?

Yes, optometrists do diagnose photokeratitis. An optometrist will need to run a comprehensive eye exam which can assess any damage in different regions of the eye. If you are experiencing symptoms of photokeratitis, your local doctor may also examine your eyes to detect photokeratitis symptoms.

What are the Treatments for Photokeratitis?

The ways to treat photokeratitis may include placing a cold damp cloth over your closed eyes, artificial tears, pain relief medication and taking prescribed antibiotics. The suggested treatments for photokeratitis are listed below.

Placing a Cold Damp Over Your Closed Eyes: Placing a cold cloth damp over your closed eyes may help soothe and cool the eyes during photokeratitis.
Artificial Tears: Artificial tears may be prescribed by an optometrist and can help with restoring moisture in the eyes, which may alleviate the gritty sensation and general discomfort.
Pain Relief Medication: Pain relief medication may be prescribed to reduce eye pain caused by photokeratitis.
Taking Prescribed Antibiotics: Taking prescribed antibiotics from an optometrist as advised may help treat a possible infection that may have developed from photokeratitis.

Is Photokeratitis Curable?

Yes, photokeratitis is curable. Therefore, it is important to go to an optometrist as they will be capable of providing the most suitable form of treatment to cure photokeratitis. However, it is also important to take certain safety steps to prevent it from recurring. Avoiding long hours of exposure to sunlight and wearing protective eyewear when handling tools that involve UV light may help prevent UV exposure.

Can Eye Drops Get Rid of Photokeratitis?

Yes and no, eye drops may get rid of photokeratitis symptoms or prevent an infection, however, this depends on the severity of your condition. Photokeratitis may also heal on its own without treatment according to the Cleveland Clinic. However, it is still advisable to see your optometrist as they can professionally determine the extent of the damage in your eyes. Photokeratitis eye drops may include antibiotic eye drops and artificial tear eye drops as prescribed by your optometrist and depending on the symptoms you present.

What Happens if Photokeratitis Goes Untreated?

If photokeratitis goes untreated, severe burns may result in scarring on the cornea according to Loma Linda University Health. It is important to seek treatment from an optometrist or GP as symptoms can continue to provide discomfort or pain for the patient. It may also help prevent the development of possible ocular complications.

Should Photokeratitis Be Treated?

Yes, photokeratitis should be treated as it can present symptoms that are painful and unpleasant for the patient. Therefore, an optometrist will be capable of prescribing appropriate treatment for your symptoms.

Is Photokeratitis Dangerous?

Yes, photokeratitis can be dangerous, as a build-up of UV light exposure over time may lead to an increased risk of macular degeneration or cataracts and other eye complications.

Can Photokeratitis Cause Blindness?

Yes and no, photokeratitis may not cause blindness, when experiencing it, however, increased exposure to UV radiation throughout your life may lead to reduced or poor vision in later years.

What are Some Ways to Avoid Photokeratitis?

Some ways to avoid photokeratitis may include changes to your recreational activities and exercising more protective steps. You may be able to avoid developing photokeratitis by limiting time spent in the direct sun if your activities frequently involve being outdoors, limiting the use of tanning beds and booths and using protective eyewear if you handle tools that emit UV light.

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