Originally posted by: Booster
Originally posted by: So
Oh, and to prove my point....shine the laser on something else (say, your hand) -- it doesn't even get warm! Shine one of the lasers that they use for surgery on a plastic cup and it will begin to melt pretty fast.
Well IMO it's not the power itself that could damage one's vision. It's the light - overly bright, highly focused. No matter what people in this thread say, I'm still pretty sure any kind of laser isn't safe.
I can't believe it. The usually clever and tech-savvy ATOT is proving to be such a klutz tonight.
Laser pointers have the potential to cause serious damage to the eye. I myself can attest to this fact. Once someone shone a pointer in my eye for about 10 seconds. I had mild throbbing pain in the eye for about a week.
Here, educate yourselves and stop being such idiots:
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Laser Pointers
The Issue
Hand-held laser pointers are popular in Canada. Unfortunately, users are not knowledgeable about the intensity of the light and the effect it may have on the eye.
If you look directly into the beam from a laser pointer for more than a minute and a half in a very steady manner, or shine the beam into your eyes with binoculars, you could end up with permanent eye damage.
Background
Laser technology was first developed in the 1960s, and has grown to touch our lives in many ways. We use laser technology in space-age medical equipment, office printers and light shows at rock concerts.
A laser is the strongest source of light ever created by scientists. The beam that comes out of a simple hand-held laser pointer is at least a million times brighter than the average light bulb in your home.
The letters in "laser" stand for Light Amplification by Stimulated Emission of Radiation
Concern about Laser Pointers
These pointers are not dangerous when used with care, but the brightness of laser light can damage the eyes of anyone who looks directly into the beam for more than a minute and a half.
A split-second look can result in a condition called flashblindness. This is similar to the effect you get during flash photography, where the image of the flash remains in your eyes for a few seconds, and then fades away.
Flashblindness is temporary. Your vision returns to normal after a few moments, and there are no long-term effects. However, a longer look can cause serious damage to your eyes. It's worse if the laser beam is being projected through a piece of optical equipment, such as a telescope or a pair of binoculars. In these situations, the laser beam could actually burn a tiny spot, or cut open a blood vessel, on the retina at the back of your eye. In a worst-case scenario, you could go blind.
Use Common Sense
Laser pointers are not toys. Use them with caution, and only for their intended purpose. So far, there have been no reports of permanent eye damage caused by the use of laser pointers in Canada. We can keep it that way if we use our common sense. By following a few guidelines you can make sure no one gets hurt by a laser pointer. For example:
* When you buy a laser pointer, choose one that has a clear warning on the label about the potential to cause eye damage. Read the instructions carefully, and follow them closely.
* Choose a laser pointer that stays on only when you apply pressure with your fingers. That way you can never leave the beam on by accident.
* Never point a laser beam at anyone, and never look directly into the beam yourself.
* Never aim a laser pointer at surfaces that would reflect the light back, such as mirrors or mirrored surfaces.
* Never leave a laser pointer where children might get their hands on it.
http://www.hc-sc.gc.ca/english/iyh/products/laser.html
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Health Concerns of Hand Held Laser Pointers
Laser pointers
Laser pointers are small hand held lasers, originally designed for use by lecturers, to draw attention to particulars on a slide or overhead projection. Recently, lower cost solid state diode lasers have become available that are smaller and more rugged than the earlier gas lasers. These new diode laser pointers are also being marketed widely as novelty items.
The brightness (radiant intensity divided by the area of the emitting surface) of the light from these small lasers is greater than that of the sun, even at a large distance. There have been reports in Canada, the U.S.A. and other countries of incidents where laser pointers have been targeted at bus drivers, police officers, firefighters, musicians, teachers, audiences and athletes.
Are lasers dangerous?
That depends upon the output power of the laser. Very low power lasers are safe. Moderate to high power lasers can be hazardous to the eyes and, in some cases, the skin. Countries such as the U.S.A., where many diode laser pointers come from, have laser safety standards with mandatory classification and labeling requirements. In this system, all lasers are classified into one of four classes. The classification number (one to four) and appropriate warning statements must be labeled on the device. A class 1 laser does not present a hazard.
* A class 2 laser is visible, not inherently safe, but the eye is protected by one?s "blink aversion response" to the bright light.
* Class 3 lasers fall into one of two sub-classes, i.e., 3a and 3b.
o Class 3a: For most individuals, eye protection is afforded by the "blink aversion response" to class 3a lasers, except when the laser is viewed using optical aids (telescopes, binoculars).
o Class 3b lasers are dangerous, and can damage eyes instantaneously upon exposure. They require a longer exposure time to burn skin.
* Class 4 lasers are dangerous, and can damage eyes and skin instantaneously upon exposure. Some can damage eyes even from a diffuse reflection. Class 4 lasers can cause materials to ignite.
Diode laser pointers
Are diode laser pointers hazardous?
A survey of laser pointers available for retail sale in BC's Lower Mainland revealed that class 3a diode lasers, emitting mostly red light are being sold. Because they are lasers, injury to the retina can occur for individuals using optical aids (binoculars, telescopes). The natural "blink aversion response" would be unlikely to provide adequate protection from eye injury for intrabeam viewing of class 3a lasers through these devices. Class 3a laser pointers when viewed briefly without optical aids are unlikely to damage the eyes for individuals unless they force themselves to overcome their natural "blink aversion response" and stare into the bright laser light.
Other concerns?
* If a person?s eyes are exposed to a momentary sweep of the light from a laser pointer, this may result in temporary flash blindness. This is a bright dazzling flash, which is likely to cause distraction, temporary loss of vision in the affected eye and possible after-images.
* This can be dangerous if the exposed person is engaged in a vision-critical activity such as driving or operating machinery, playing sports, etc.
Exposure
If you were accidentally exposed and an after-image(s) persists for hours, or if a disturbance in reading vision is apparent, then medical attention should be sought. Secondly, report the incident to your local environmental health office (public health department).
Conclusions
1. Laser pointers, including diode laser pointers, are useful tools that should not be used by children or irresponsible individuals.
2. In some countries the sale of class 3a laser pointers is banned. It is recommended that the use of laser pointers be restricted to devices in classes 1 or 2 in preference over the class 3a, diode laser pointers.
3. Retailers should be discouraged from selling class 3a laser pointers the general public.
4. The control of the importation and sale of radiation emitting devices, such as lasers, is the responsibility of the federal government. No regulations controlling the importation and sale of laser pointers have been established in Canada to date.
http://www.bccdc.org/content.php?item=54