Posted by: pswi60 | September 4, 2008

Debunking the Laser Blindness Myth

Recently, I was working on a playstation 2 that stopped reading discs. The ps2 was notorious for its lasers burning up or being out of alignment. So while reading a tutorial from arstechnica on how to realign the laser, there was a warning about looking at the laser. Here is a quote from that tutorial:

“During the repair of your Playstation 2, we’ll be taking the device apart. Most of the supports will be taken out, so be careful you don’t bend or break any of the connectors on the various ports or internally. We’ll also be taking apart the loading tray. This includes a Class 1 laser, which can blind you. The easiest precaution is to make sure your PS2 is left off when the disc tray is open.

Now, this wouldn’t be an issue, had I not caught myself staring into the red ps2 laser after I had made adjustments to it. I was mesmerized by the laser moving up and down trying to read the disc. After I caught myself doing it, and realized I had been staring into the laser, my first thought was I was probably going to be blind.

Being a hypochondriac already, I instantly searched the internet for anything I could find about lasers, specifically the ps2 laser and how powerful it is. What I found though was rather interesting: lasers, especially those installed in home electronics, are not as dangerous as people think. Here is a breakdown of the amount of exposure you can receive from each class of laser from the University of Kentucky:

  • Class I lasers are low powered devices that are considered safe from all potential hazards. Some examples of Class I laser use are: laser printers, CD players, CD ROM devices, geological survey equipment and laboratory analytical equipment. No individual, regardless of exposure conditions to the eyes or skin, would be expected to be injured by a Class I laser. No safety requirements are needed to use Class I laser devices.
  • Class II lasers are low power (< 1mW), visible light lasers that could possibly cause damage to a person’s eyes. Some examples of Class II laser use are: classroom demonstrations, laser pointers, aiming devices and range finding equipment. If class II laser beams are directly viewed for long periods of time (i.e. > 15 minutes) damage to the eyes could result. Avoid looking into a Class II laser beam or pointing a Class II laser beam into another person’s eyes. Avoid viewing Class II laser beams with telescopic devices. Realize that the bright light of a Class II laser beam into your eyes will cause a normal reaction to look away or close your eyes. This response is expected to protect you from Class II laser damage to the eyes.

  • Class IIIa lasers are continuous wave, intermediate power (1-5 mW) devices. Some examples of Class IIIa laser uses are the same as Class II lasers with the most popular uses being laser pointers and laser scanners. Direct viewing of the Class IIIa laser beam could be hazardous to the eyes. Do not view the Class IIIa laser beam directly. Do not point a Class IIIa laser beam into another persons eyes. Do not view a Class IIIa laser beam with telescopic devices; this amplifies the problem.
  • Class IIIb lasers are intermediate power (c.w. 5-500 mW or pulsed 10 J/cm²) devices. Some examples of Class IIIb laser uses are spectrometry, stereolithography, and entertainment light shows. Direct viewing of the Class IIIb laser beam is hazardous to the eye and diffuse reflections of the beam can also be hazardous to the eye. Do not view the Class IIIb laser beam directly. Do not view a Class IIIb laser beam with telescopic devices; this amplifies the problem. Whenever occupying a laser controlled area, wear the proper eye protection. Refer to the University of Kentucky Laser Safety Manual for complete instructions on the safety requirements for Class IIIb laser use.
  • Class IV lasers are high power (c.w. >500mW or pulsed >10J/cm²) devices. Some examples of Class IV laser use are surgery, research, drilling, cutting, welding, and micromachining. The direct beam and diffuse reflections from Class IV lasers are hazardous to the eyes and skin. Class IV laser devices can also be a fire hazard depending on the reaction of the target when struck. Much greater controls are required to ensure the safe operation of this class of laser devices. Whenever occupying a laser controlled area, wear the proper eye protection. Most laser eye injuries occur from reflected beams of class IV laser light, so keep all reflective materials away from the beam. Do not place your hand or any other body part into the class IV laser beam. The pain and smell of burned flesh will let you know if this happens. Realize the dangers involved in the use of Class IV lasers and please use common sense. Refer to the University of Kentucky Laser Safety Manual for complete instructions on the safety requirements for Class IV laser use.

So there you have it….if you are working on any type of video game console, which is typical these days, you should be aware of the risks, but also know that the risks for these types of devices are generally low. As long as you are not deliberately looking into the laser despite your eyes desperately wanting to blink, you should have nothing to worry about. Looking into a laser of this type (typically Class 2 or less for all consoles) it may cause temporary blind spots, but so will looking at most bright lights or the sun. Just listen to your eyes and you should be good to go.

Happy Modding!!!

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Responses

  1. The reason CD/DVD players are designated Class I is because in normal operation the laser is not exposed to the user. Not because the laser radiation emitted by the lens is inherently safe.

  2. When modding or opening the PlayStation unit, obviously you are using the device in ways outside of normal operation.

  3. Joe, you are wrong. The class system is in place to designate the power of a laser. Regardless of whether the user is exposed during normal operation or not, has no bearing on what class the laser will fall into.

    For example, the ps2 laser could be class 3 regardless of whether the user is exposed to it.

    The fact is that Class 1 lasers aren’t that powerful, and do not required any safety requirements to use them.

  4. Hi pswi60

    Joe is right in saying that CD/DVD players are class I because the laser is enclosed. This is specified in the standards for laser safety.

    When you take it apart, your eye can potentially be exposed to the full laser power (a few mW for a CD/DVD player). It generally won’t create any damage to your eyes if you view it by accident, but intentional viewing is not recommended.

    A word of caution for CD/DVD burners: those are much higher power and you’d need to wear laser safety goggle

  5. Nice review! Good job. thanks

  6. Admin, thanks for review! Nice job.

  7. Good staff, thanks for review!

  8. Nice! Respect for the review.

  9. Hi admin, nice review!

  10. […] this may sound like an easy one but actually, lasers are far more powerful than we […]


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