The word “radiation” often brings to mind radioactivity and nuclear power. However, this is just one type of radiation. Another type is electromagnetic radiation. Everyone encounters electromagnetic radiation when they turn on a light or step outdoors on a sunny day. Visible light is but one portion of the entire electromagnetic spectrum. Light just beyond the visible spectrum such as ultraviolet, and to a lesser extent, infrared, can damage the eyes after sufficient exposure. Ultraviolet (UV) light is the most commonly encountered radiation hazard in the workplace.
Work situations that expose the eyes to electromagnetic radiation hazards include:
Workers who spend a lot of time outdoors such as landscapers, farmers, and construction workers, get plenty of sun. Unfortunately, sunlight contains ultraviolet light, which causes a slow and cumulative damage to the eyes. Because there’s no immediate feedback from UV exposure such as pain, you wouldn’t know that anything is wrong until later in life when eye problems such as macular degeneration and cataracts threaten your vision. In situations of intense UVB exposure, a temporary blindness (snow blindness) can occur.
If your job requires impact resistant safety glasses, you can get safety or prescription safety glasses made from polycarbonate or Trivex. Both of these materials have a high impact strength and naturally block out all UVA and UVB radiation. On the other hand, if you work outdoors but eye protection isn’t required, you should get UV blocking sunglasses.
Sometimes there are work situations where eye protection isn’t a formal requirement, yet involve occasional exposure to a mechanical eye hazard such as a power tool. This is the situation for some landscaper employees, for example. In these instances, impact resistant safety or prescription safety glasses take care of both mechanical and UV hazards.
The brilliant arc produced by welding emits three forms of radiation: ultraviolet, visible light, and infrared. UV radiation presents the greatest hazard to the welder in the form of “arc eye.” This is similar to snow blindness and is caused by UVB radiation. UVB lacks the penetrating power to get past the outermost layer of the cornea. Instead, it’s absorbed by this layer where it does its damage. The cornea is the transparent “window” that allows visible light to enter the eye.
UVB essentially “sunburns” the cornea, causing its outer cells to die and flake off. This produces blindness and intense pain that feels like sand in the eyes. Arc eye takes a few hours after UV exposure to develop. The blindness and pain are temporary and last about one or two days, after which, the eye completely recovers. Multiple occurrences of arc eye can cause permanent damage.
The visible light emission from welding has a dazzling effect that isn’t permanent if the welder quickly closes his eyes. Repeated exposure however, may cause a loss of visual acuity.
The infrared emission from welding is radiant heat. Years of exposure can make the eye lens cloudy, a condition sometimes called glassblower’s cataract. This generally isn’t a problem with welders because the hazard only exists at short distances (less than 3 feet) from the welding arc. In addition, the unprotected welder would immediately react to the heat felt by his skin and eyes.
Welders protect themselves with dark tinted glass plates that block the harmful radiation emissions and cut down the visible light in order to avoid being dazzled by the welding arc. The plates are installed in a shield or mask that covers the face.
Another radiation hazard present in a smaller portion of the workforce is lasers. This hazard is unique in that lasers can emit beams in the infrared, visible light, and ultraviolet spectrums. Lasers of sufficient power can damage the eyes in all of these spectrums, including visible light. That is, a laser of sufficient power will harm your eyes regardless of the type of light it emits.
With some lasers, you can’t blink your eye fast enough to avoid an eye injury. Lasers are also unusual in that they can inflict eye damage over long distances. Using powerful lasers without safety glasses means that a moment of absent-mindedness can cause permanent blindness.
Common causes of laser accidents (when not wearing safety glasses) include accidental exposure to a misaligned laser beam, accidental laser reflections, equipment malfunction, and assuming a laser is off when it’s on. Human factors include fatigue, haste, and complacency.
If you need safety glasses or prescription safety glasses, we supply protective eyewear for a wide range of work environments. For answers to your questions, contact us.