A flash burn, also known as photokeratitis, is an acute, temporary injury to the eye resulting from overexposure to intense ultraviolet (UV) light. This condition is essentially a sunburn on the surface of the eye, often caused by sources like welding arcs, sunlamps, or reflected sunlight off snow or water. The injury affects the cornea, the clear, dome-shaped tissue at the front of the eye, but is generally treatable with a high rate of full recovery.
What is a Flash Burn and Why Does it Hurt
A flash burn occurs when the eye’s outer protective layer, the corneal epithelium, absorbs high levels of UV radiation. This UV exposure damages the cells on the surface of the cornea. Since the cornea is a highly sensitive structure, the resulting cellular damage leads to inflammation and the development of thousands of tiny abrasions on its surface.
The irritation from these microscopic injuries causes intense pain and discomfort. Symptoms are often delayed, usually starting 6 to 12 hours after the exposure. Common signs include a sensation of grittiness or a foreign body in the eye, excessive tearing, redness, and extreme sensitivity to light (photophobia). The intense pain signals that the protective barrier of the cornea has been compromised.
Initial Response and Treatment
Immediate action upon recognizing symptoms includes removing contact lenses and avoiding the urge to rub the eyes, which can worsen the damage. Seeking medical attention is important because self-treating a corneal injury can lead to complications like infection. While waiting for professional care, applying a cold compress over the closed eyelids helps reduce inflammation and provides temporary relief.
A medical professional focuses on pain management, preventing infection, and supporting the cornea’s natural healing process. Oral pain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), are recommended to manage severe discomfort. To prevent secondary bacterial infection, a broad-spectrum topical antibiotic (drops or ointment) is typically prescribed for several days.
In some cases, a doctor may use cycloplegic drops to temporarily paralyze the ciliary muscles of the eye, relieving pain caused by muscle spasms. Artificial tears or lubricating eye drops are also standard treatment to keep the ocular surface moist and aid healing. The use of a temporary eye patch is less common, as it can increase the risk of infection, but it may be used to allow the eye to rest.
The Typical Recovery Timeline
The duration of a flash burn is determined by the corneal epithelium’s ability to regenerate quickly. Symptoms typically peak between 6 and 24 hours after UV exposure. Fortunately, the majority of mild to moderate cases resolve completely within 24 to 72 hours.
This rapid healing depends on the severity of the burn and compliance with prescribed treatments. Longer exposure to the UV source, such as a welding arc or tanning lamp, results in more extensive epithelial damage. This may push recovery toward the 72-hour end of the spectrum. Following instructions for antibiotic and lubricating drops is important to ensure a smooth recovery and prevent complications.
While intense pain and foreign body sensation usually subside within 72 hours, some patients may experience residual symptoms. Mild light sensitivity or slightly blurred vision can linger for a few additional days as the cornea fully stabilizes. If pain or decreased vision persists beyond 72 hours, or if symptoms worsen after initial improvement, immediate follow-up medical care is necessary to rule out complications like secondary infection.
Preventing Future Exposure
Prevention is achieved by using appropriate protective eyewear. When working with welding equipment, a helmet with a UV-protective lens and the correct shade rating is essential to block intense UV radiation from the arc. Others working nearby should also be protected, or UV-blocking screens should be used to contain the light.
In outdoor environments, especially those with high reflectivity, protective measures are necessary. Activities like skiing, fishing, or being on the water require wraparound sunglasses that block 100% of both UVA and UVB rays to prevent injury, sometimes called “snow blindness.” Artificial UV sources, such as tanning beds and germicidal UV sterilizing lights, also require specific protective goggles.