A flash burn, commonly known as “arc eye” or “welder’s flash,” is a painful eye condition caused by exposure to intense ultraviolet (UV) radiation from a welding arc. This injury is technically classified as photokeratitis, a temporary inflammation of the cornea. The cornea is the clear, dome-shaped surface at the front of the eye. The condition is analogous to a severe sunburn on the eye’s surface, resulting in significant discomfort and requiring attention.
Understanding the Cause and Mechanism
The intense light generated by a welding arc emits high levels of invisible UV radiation, specifically in the UVC and UVB wavelengths. When the eye is exposed without adequate protection, the UV light is absorbed by the cornea’s outer layer, called the epithelium. This concentrated energy absorption chemically damages the superficial epithelial cells, triggering a process similar to a sunburn. The damaged cells eventually slough off, exposing the highly sensitive nerve endings beneath the epithelial layer, which causes the characteristic and often severe pain associated with a flash burn.
Identifying Acute Symptoms
A defining feature of photokeratitis is the delayed onset of discomfort, typically beginning 6 to 12 hours following exposure. This delay often means severe eye pain starts in the middle of the night. The most common experience is a foreign body sensation, often described as feeling like sand or grit trapped inside the eye.
This sensation is accompanied by intense photophobia (sensitivity to light) and excessive tearing. The eyes may appear visibly bloodshot due to inflammation, and some individuals report temporary blurred vision. Both eyes are usually affected, though the eye that received the most direct exposure may experience more intense symptoms.
Immediate Care and Recovery
Upon experiencing symptoms, the priority is to seek professional medical attention to confirm the diagnosis and prevent complications. Until medical help is available, applying a cool, damp compress over the closed eyelids can help reduce inflammation and provide temporary relief. Avoid rubbing the eyes, as this action can further damage the compromised corneal surface and increase the risk of secondary infection.
Medical treatment usually focuses on pain management and infection prevention. Doctors may prescribe oral non-steroidal anti-inflammatory drugs (NSAIDs) for pain, and antibiotic eye drops or ointments are often used to guard against bacterial infection. Topical anesthetic drops are sometimes used by a physician for examination but are never prescribed for home use because they can delay healing. The recovery process is rapid, with most flash burns healing completely within 24 to 48 hours without permanent vision loss.
Preventing Arc Eye Exposure
Preventing a flash burn requires protecting the eyes from the welding arc’s radiant energy. This involves the consistent use of appropriate Personal Protective Equipment (PPE), most notably a welding helmet with a filtered lens. The lens shade rating must be selected based on the welding process and the amperage being used.
For most arc welding processes, a filter shade of 10 or higher is required to block the intense UV light effectively. Bystanders must also be shielded from the arc by using non-reflective welding screens or curtains, as indirect exposure can cause a burn. Ensuring the helmet is properly fitted and lowered before striking the arc is a simple, effective step to guarantee continuous protection.