“Welder’s flash,” also known medically as photokeratitis or arc eye, is a temporary but intensely painful eye condition resulting from unprotected exposure to high levels of ultraviolet (UV) light. This injury is essentially a sunburn that affects the cornea, the clear, dome-shaped front surface of the eye, and the conjunctiva. The intense UV radiation produced by a welding arc damages the outer layer of the cornea, called the epithelium. While welding is the most common cause, photokeratitis can also result from other UV sources, such as sunlamps or bright light reflecting off snow (“snow blindness”).
The Sensation and Symptoms
The most distinct sensation of welder’s flash is described as having coarse sand or grit trapped within the eyes, ranging from irritating to severely painful. This feeling occurs because UV-damaged corneal cells slough off, leaving underlying corneal nerves exposed and highly sensitive. The pain is typically throbbing or sharp and often affects both eyes simultaneously, making it difficult to keep them open. A primary symptom is photophobia, a hypersensitivity to light that makes bright environments unbearable. The eyes often appear red or bloodshot due to inflammation, producing excessive tears (lacrimation), and blurry or decreased vision is also common.
Understanding the Delay and Duration
A defining characteristic of welder’s flash is the delayed onset of discomfort, as the initial UV exposure is not immediately painful. Symptoms typically begin to manifest between 4 and 12 hours after exposure, due to the time it takes for the damaged corneal cells to die and detach. The pain and other symptoms often worsen at night, likely because the eyelids rub against the damaged corneal surface. Fortunately, photokeratitis is temporary because the corneal epithelium regenerates quickly. The intense symptoms usually resolve completely within 24 to 48 hours, with the cornea typically healing itself without scarring if managed properly.
Immediate Care and Professional Treatment
Immediate self-care focuses on reducing pain and preventing further irritation when symptoms begin. Resting the eyes in a dark environment and applying a clean, cold compress helps soothe inflammation and relieve discomfort. Over-the-counter artificial tears or lubricating eye drops can also be used to keep the eye surface moist and reduce friction. Avoid rubbing the eyes, as this can worsen corneal damage and potentially introduce infection. Professional medical evaluation is necessary if the pain is severe, vision changes drastically, or if symptoms persist beyond 48 hours; a doctor may prescribe antibiotic drops or muscle-paralyzing medication.
Preventing Recurrence
Welder’s flash is entirely preventable by using appropriate protective equipment that blocks intense ultraviolet radiation. The shield for a welding helmet contains a specialized filter lens indicated by a shade number, which ranges from 2 to 14. A higher shade number corresponds to a darker filter that blocks a greater amount of light and radiation. The required shade depends on the welding process and electrical current used, such as shades 10 to 13 for metal inert gas (MIG) welding. Ensuring the helmet fits correctly and that all nearby workers are also protected from the arc flash eliminates the risk of recurrence.