Looking at welding light is dangerous to your eyes. The intense light produced by the welding arc is a powerful source of concentrated electromagnetic radiation, including invisible forms. This radiation can cause damage to the eye’s delicate tissues in both the short and long term. The primary danger comes from the non-visible parts of the spectrum, which can lead to injuries even with brief exposure.
The Invisible Danger: Why Welding Light Damages Eyes
The welding arc generates radiation across a broad spectrum, including ultraviolet (UV), visible light, and infrared (IR) radiation. These energy waves are absorbed by various eye structures, leading to distinct forms of damage. UV radiation is divided into UV-A, UV-B, and UV-C. UV-C and most UV-B are absorbed by the cornea, the clear outer layer of the eye. UV-A radiation passes through the cornea and is absorbed primarily by the lens.
IR radiation, which is felt as heat, is also emitted by the arc and penetrates the eye deeper than most UV light. Both IR and some visible light can reach the retina, where the light-sensing cells are located. Brief exposure to an unprotected arc can overwhelm the eye’s natural defenses, causing cellular damage that underlies all welding-related eye injuries.
Immediate Effects: Understanding Arc Eye
The most common acute injury from welding light exposure is photokeratitis, widely known as “arc eye” or “welder’s flash.” This condition is essentially a painful sunburn of the cornea and the conjunctiva, caused by intense exposure to UV radiation, particularly UV-C and UV-B. Symptoms are characteristically delayed, typically appearing 6 to 12 hours after exposure, making it difficult to immediately connect the pain to the welding activity.
The onset is marked by intense, excruciating pain, often described as a foreign body sensation, like having sand or grit in the eyes. This is accompanied by significant sensitivity to light (photophobia) and excessive tearing. The temporary damage to the corneal surface leads to blurred vision and muscle spasms in the eyelids. While the symptoms are severe, the condition is usually temporary because corneal cells regenerate rapidly. The damage typically heals completely without permanent vision loss within 24 to 48 hours, though severe pain often requires medical attention for diagnosis and pain management.
Deeper Concerns: Risks to the Lens and Retina
Exposure to welding light can lead to serious, chronic damage to the internal structures of the eye, particularly the lens and the retina. The cumulative effect of repeated or prolonged exposure to UV-A and infrared radiation is a significant risk factor for developing cataracts. Cataracts involve the clouding of the eye’s lens, which impairs vision by scattering light.
IR radiation, felt as heat, can raise the temperature of the lens, accelerating the protein denaturation that leads to cataract formation over time. Both UV and IR radiation contribute to this long-term deterioration of the lens, which progresses silently until vision is significantly compromised. The most severe injury is to the retina, resulting from extremely intense or prolonged exposure to visible light and near-infrared radiation. This can cause photochemical damage or thermal burns to the macula, the central area responsible for sharp, detailed vision. Retinal damage is concerning because the retina has a limited capacity for repair, potentially resulting in permanent vision loss or blind spots.
Essential Protection and Safety Measures
Protecting the eyes from welding light requires specialized equipment that filters the entire spectrum of harmful radiation. The primary defense is a welding helmet equipped with a filter lens designed to block UV and IR radiation. The lens must be selected for the correct shade number, which determines the darkness level based on the specific welding process and amperage.
For most arc welding processes, a shade number between 10 and 14 is required; a higher number indicates a darker lens for higher currents. Matching the shade to the arc intensity is crucial, as a shade that is too light fails to protect, and one that is too dark impairs visibility. Auto-darkening helmets automatically switch from a light shade to a darker, protective shade in a fraction of a second upon sensing the arc.
Bystanders must also be protected, as the arc’s radiation can travel considerable distances and reflect off surfaces. Using protective screens or curtains around the welding area shields others from accidental exposure. If exposure occurs, applying a cool compress and taking over-the-counter pain medication can help manage immediate discomfort. Medical attention should be sought immediately if the pain is severe, if symptoms persist beyond 48 hours, or if there is any change in vision.