Photokeratitis (also known as ultraviolet keratitis, UV keratitis) is an acute, reversible eye surface injury caused by excessive exposure of the cornea to ultraviolet (UV) radiation in a short period of time. Its nature is similar to sunburn, but the damaged tissue is not the skin, but the corneal epithelium. This condition is often caused by strong sunlight, reflected UV radiation, or artificial UV light sources. When it occurs, it can cause significant and severe eye pain and discomfort, and is therefore often vividly referred to as "sunburn of the eyes."This article will systematically introduce the main causes, typical symptoms, and clinical management of photokeratitis, and further explain scientific and effective preventive measures to help you better protect your vision health in daily life and special environments.Photokeratitis: Causes and Risk FactorsPhotokeratitis is an acute eye surface injury caused by short-term exposure to excessive ultraviolet (UV) radiation without adequate protection. UV radiation directly damages corneal epithelial cells, affecting the cornea, the transparent tissue covering the surface of the eyeball; in some cases, the conjunctiva (the mucous membrane covering the white of the eye and the inside of the eyelids) is also affected. Clinical studies show that both UVA and UVB have potential ocular toxicity and can contribute to the development of photokeratitis.Outdoor activities are a significant risk factor for this condition, especially in environments with significantly increased UV intensity, such as high-altitude areas, low-latitude regions, or during periods of strong sunlight. When UV radiation is reflected by highly reflective surfaces such as snow, ice, water, or sand, the effective radiation dose entering the eye increases significantly, greatly increasing the risk of corneal damage. Furthermore, directly looking at the sun (including during a solar eclipse without professional viewing equipment) can cause severe corneal photodamage in a short period.Snow BlindnessSnow blindness is a typical manifestation of photokeratitis, primarily caused by strong sunlight reflection from ice and snow surfaces. This condition is common in polar regions or high-altitude environments where the air is thinner and UV radiation is stronger. However, people engaged in activities such as skiing, mountaineering, or snowmobiling in other areas are also at risk of developing snow blindness. Therefore, wearing goggles with effective UV protection in snowy environments is a crucial preventive measure.Other UV-Related TriggersIn addition to natural sunlight, various artificial UV light sources can also cause photokeratitis, including but not limited to:Sunbeds or tanning booths with strong UV outputArc welding equipment (commonly known as "welder's eye")High-intensity floodlights used in photography or film productionLaser light sourcesHalogen lamps and some high-brightness industrial or road lighting equipmentThe intense light released instantaneously by electrical sparks and lightningTypical Symptoms of PhotokeratitisThe clinical manifestations of photokeratitis share a similar delayed characteristic with sunburn; symptoms typically do not appear immediately after ultraviolet (UV) exposure but gradually develop several hours later. Generally, the longer the duration and higher the intensity of UV exposure, the more severe the corneal damage and the more pronounced the symptoms. It is particularly important to note that frequent or forceful rubbing of the eyes will further irritate the damaged corneal epithelium, exacerbating the inflammatory response and discomfort; therefore, this should be avoided as much as possible.Common symptoms of this condition include, but are not limited to:Significant eye pain or stinging sensationBurning or stinging discomfort in the eyesConjunctival hyperemia, manifesting as red eyesTemporary decrease in vision or blurred visionIncreased tearingMild swelling of the eyelids or surrounding tissuesAbnormal sensitivity to light (photophobia)A distinct foreign body sensation, often described as "sand in the eyes"Accompanying headacheInvoluntary eyelid twitchingTransient visual disturbances, such as halos or glare around lights or bright objectsHow long does photokeratitis last?In most patients, photokeratitis gradually subsides and resolves within 24–48 hours. Although the symptoms are usually temporary and reversible, it's important to emphasize that prolonged or repeated exposure to strong ultraviolet light can cause cumulative damage to eye tissues, increasing the risk of developing chronic eye diseases such as cataracts and macular degeneration.Treatment and Management Principles for PhotokeratitisIf photokeratitis is suspected, it is recommended to seek professional evaluation from an optometrist or ophthalmologist as soon as possible. Eye care professionals can accurately assess the extent of corneal damage and develop a targeted treatment plan based on the specific situation to alleviate symptoms and prevent complications.Common clinical management recommendations include:Reducing light exposure: Staying in a dimly lit environment can help relieve photophobia and eye discomfort.Discontinuing contact lens wear: Contact lenses should be immediately removed until symptoms completely disappear to avoid further corneal irritation.Appropriate use of eye drops: The doctor may recommend artificial tears to lubricate and protect the cornea; if there is a risk of infection, antibiotic eye drops may also be used for a short period.Cold compresses: Applying cold compresses to the closed eyes can effectively reduce eyelid swelling and local discomfort.Using pain medication when necessary: Taking pain medication under the guidance of a doctor can help relieve pain and discomfort.How to Effectively Prevent PhotokeratitisThe key to preventing photokeratitis lies in reducing direct or indirect exposure of the eyes to strong ultraviolet (UV) radiation. Any high-intensity UV light source can damage the cornea, with the most typical risky behavior being looking directly at the sun. It is crucial to emphasize that viewing a solar eclipse without protection can cause serious eye damage; if you need to observe a solar eclipse, you must use professional eclipse viewing glasses or equipment that meets safety standards.In daily life and during specific work or sports activities, wearing appropriate protective eyewear is a key preventive measure. When engaging in outdoor activities, choose sunglasses that effectively block both UVA and UVB radiation; in highly reflective environments such as snow or ice, it is recommended to use snow goggles or safety glasses with comprehensive UV protection. For individuals exposed to occupational hazards such as welding, strictly wearing professional protective equipment that meets industry standards can significantly reduce the risk of photokeratitis.If you experience suspected symptoms such as eye pain, photophobia, or blurred vision, or have any concerns about your eye health, you should schedule an eye examination promptly to receive professional assessment and guidance. By establishing good eye protection habits and actively avoiding high-risk light sources, you can effectively protect your corneal health and reduce the probability of developing photokeratitis, which is crucial for maintaining visual safety in the long run.
