Why Recreational Laser Users and Hobbyists Need Laser Safety Glasses
Slingshots, bb guns, darts, and power tools are often used for recreational or hobby activities. All of these items are eye hazards, and require appropriate eye protection. They’re hazardous because they can cause serious injury and even blindness. However, their mechanical nature makes their danger intuitively obvious to most people. If one chooses to forgo eye protection, they do so with full awareness of the danger.
On the other hand, the hazards of lasers seem less physically obvious and more abstract. The difference between a harmless and a hazardous laser is difficult to ascertain by its appearance or behavior while in use. One only knows by reading its labeling. This makes accidental injury more likely. Habits developed from using “harmless lasers” can cause an eye injury when using more powerful ones. Laser beams have a long range and can accidentally damage your eyes, or that of bystanders. They are silent, and some types of laser beams are invisible.
Why the Blink Reflex Will Not Always Save Your Eyes
The blink reflex to a bright light source is fast enough to prevent eye injury when exposed to class 1, 2, and 3R lasers. However, it isn’t fast enough for avoiding injury from higher powered lasers. If cavalier laser usage causes frequent accidental eye exposure, the same bad habits when using more powerful lasers can seriously damage the eyes.
Another danger lies with some laser products imported from other countries. Some countries have sub par safety standards and may leak invisible but potentially harmful infrared laser light. In addition, you shouldn’t implicitly trust the labeling of imported lasers. There’s a strong economic incentive to mislabel lasers in order to comply with U.S. Import requirements.
The blink reflex only occurs when exposed to visible light. Infrared lasers are invisible and awareness of its exposure only occurs from the inflicted eye damage, which by then, is too late. Near-infrared (IR-A) lasers penetrate deeply into the eye and damage the retina. The retina is at the back inside surface of the eyeball. Its light sensitive cells generate nerve impulses to the brain. IR-A does its damage by generating heat. Mid-infrared (IR-B) and far-infrared (IR-C) damage the outer transparent layer of the eye, called the cornea. The extent of the damage depends on the beam’s intensity and duration. Note that retinal damage (caused by IR-A) is permanent.
What the above means is that wearing laser safety glasses should be a habit when using lasers beyond class 1 and 2. Lasers used in many recreational activities and hobbies are often class three and even class 4. Here are three examples of this:
Handheld Laser Guns
These are not the toys used for laser tag. They are the real thing. That is, they are hand held guns that emit laser light capable of burning holes through plastic, wood, and other materials. A favorite target for these is balloons. Although foreign companies sell these online, the U.S. is one of the countries many will not ship to. In spite of this, many people here find ways of acquiring them. The power output of these lasers can be between one and three watts, which places them well into the class 4 laser range (0.5 watt and higher).
Clearly, the person using the gun and bystanders should wear laser safety glasses. The main danger is eye exposure to accidental reflection of the beam off reflective surfaces. These can be mirrors, glass, metal, crystalline materials, or composite materials with reflective components. In addition, looking at the spot lit up by class 4 lasers, regardless of its reflectivity, can cause injury to unprotected eyes. For example, staring at a laser spot on a concrete wall will injure unprotected eyes.
Many tech minded people enjoy building their own lasers. Generally, the components are bought separately and assembled together by hand. Some people have converted CD disc-writing lasers into burning lasers that burn holes through cardboard, plastic, and wood. With some know-how, powerful lasers can be assembled. Any laser above one watt in power is very risky to oneself and others. The dangers of homemade high-powered lasers are the same as those discussed in the previous section. Make sure that the laser safety glasses used are rated to handle your device’s power.
Laser Cutters And Engravers
These are self contained machines that have a movable laser head that can etch patterns into wood and other materials. They can also be used to cut 2D slices out of a material, such as wood. These slices are then glued together to form 3D objects. These devices typically use CO2 lasers, which emit a far-infrared (IR-C) laser beam. Quality, well designed machines in good condition normally don’t expose the eyes to stray laser light. Nevertheless, many manufacturers recommend laser safety glasses.
Old machines experience wear and tear, and may become damaged in ways that can expose the eyes to laser light. Because the beam is infrared, it is invisible, which means you will have no awareness of this exposure until the eye damage affects your vision. In addition, used machines or cheap machines built in another country should be regarded as suspect.
Unlike the mechanical eye hazards discussed above, lasers that emit visible beams as well as near-infrared (IR-A) lasers can cause irreversible damage to the retina. With the powerful class 4 lasers previously discussed, this damage can happen in a split second.
Don’t take chances with your vision. Get laser safety glasses. In addition, you must select the correct pair that will attenuate or block the laser type (its wavelength) and its power. If you get either of these two specifications wrong, they won’t protect your eyes. For assistance in selecting the correct pair for you, please contact us.