How Long Does Photokeratitis Last?
You went outside without sunglasses on a very nice day and hours later your eyes started hurting. Sounds like a familiar story? Our eyes can be damaged by excessive UV light. This leads to a condition called photokeratitis or sunburned eyes.
The epithelium on the surface of our eye regenerates rapidly from UV light damage. Because of this, fortunately photokeratitis is a short-lived condition. Depending on the severity of the exposure to UV light, one can expect photokeratitis to resolve in approximately 24 to 48 hours.
While there is nothing you can do to “heal” it up, there are things you can do to help prevent a prolonged recovery after UV light exposure.
What Is UV Light Doing?
The visible light that we see all around us is only a small part of the entire electromagnetic radiation spectrum of light waves. Also coming from the sun is ultraviolet radiation. These UV rays are short energy waves that are responsible for giving us sunburns and increasing our risk of skin cancer. But this light also leads to short-term damage of our eyes called photokeratitis.
The very front layer of the cornea is called the epithelium. This is the “skin-like” layer on our cornea. This layer absorbs UV light and excessive amounts cause damage to these cells and cause them to die off.
Fortunately, these cells regenerate, but in the meantime the death of these cells causes our eyes to feel gritty and irritated and can cause our vision to become a little more blurry.
When Does It Resolve?
The epithelial cells of our eye are in constant production. But when there is damage to the epithelial, the production kicks up a notch.
This allows our eyes to rapidly heal up following photokeratitis. In fact, photokeratitis will only take about 24 to 48 hours to heal up. Rarely longer than that unless there is severe damage. Much of how long it takes to heal depends on how much UV light the eyes were exposed to and thus how much damage there is.
What determines your exposure (ie how long until it goes away)?
Our eyes actually have some pretty handy built-in defenses against UV light.
Immediately above our eyes is our brow bone (where the eyebrow sits). When the sun is directly overhead, the brow acts like an umbrella to shade and block the damaging UV light from hitting our eye. In addition, our eyelids also serve as natural barriers to protect our eyes.
Because of this, light has to enter our eye more directly in order for it to reach the cornea and cause damage. This is the reason why light reflecting off of snow “called snowblindness” is a very common cause of photokeratitis. Snow is very reflective and redirects light directly into our eyes.
But when else can you have high natural exposure?
- When the sun position isn’t too high in the sky. This occurs during the morning and evening and is also influenced by the season (with the sun being lower in the sky during the winter). The sun’s position is also affected by whether you are closer to the equator or closer to the poles of the earth.
- UV rays are scattered and absorbed by clouds, particles in the atmosphere and by the ozone. A lack of these things causes more UV light to reach the eyes. (the southern hemisphere, and especially over Antarctica, have high amounts of UV light due to depletion of the ozone layer and also being slightly closer to the sun than the northern hemisphere during summer)
- If you climb a mountain, the atmosphere gets thinner and less UV light will be absorbed before reaching your eyes - putting you at high risk for greater photokeratitis damage.
- While snow and ice have the greatest reflection of sun, water, green grass, sand and asphalt can also reflect higher than normal amounts.
Speeding Up Resolution
Photokeratitis needs to heal up naturally. There isn’t any secret formula that can make it instantly disappear. The damaged and dying epithelial cells need to be replaced with new healthy ones.
But while things are healing, there are some things you can do to hasten this recovery.
- Prevent further damage by wearing sunglasses. If the eye is constantly being damaged by UV light, the photokeratitis won’t heal up. The sunglasses should be rated UV400. This means that they block 99-100% of UVA and UVB rays. Even better if you find sunglasses that wrap-around and block the sides of your eyes as well - especially if you plan on being out in the snow, on the water, or at the beach where light will reflect quite highly. Fortunately, you don’t have to spend much to get quality sunglasses. But be sure to get a pair you like because otherwise you just won’t wear them.
- Other things that will slow healing is excessive inflammation on the surface of the eye. In fact, damage to the epithelium from photokeratitis will cause inflammation. Thus, helping this inflammation go away quicker can help the photokeratitis resolve quicker.
- One of the most effective ways to reduce inflammation and promote healthy and quick recovery is by taking preservative-free artificial tears. These can also make the eyes feel better in the meantime as well. Bonus tip: keep these tears cool in the refrigerator - that can be even more soothing.
- Using ibuprofen can help treat injuries all around the body and its no different when talking about the eyes. You may find some relief; although, don’t expect it to take care of everything.
- Using cool compresses or a cooling eye mask can also help the eye feel more comfortable and can help reduce the inflammation from photokeratitis by constricting blood vessels around the eye. Same way an ice pack works for other injuries.
Lastly, if the photokeratitis isn’t resolving or getting better, be sure to visit a doctor to assess your eyes and make sure nothing else unusual is going on.
Photokeratitis is a short-lived condition which will heal quickly in most cases. Often within 24-48 hours the cornea will be healed over. Preventing additional exposure to UV light with UV protection sunglasses and treating the eyes with some over the counter remedies such as artificial tears can help the eyes return back to normal quicker.
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