Lasers are classified by their power output, which is associated with their exposure safety.
|
Class of Laser |
Power Output in mW |
Eye Safety |
|
1 |
<= 0.0004 for blue or green <= 0.024 for red |
eye safe |
|
2 |
< 1 and not Class 1 |
eye safe, but brightness may cause blink and aversion |
|
3a |
1 – 5 |
eye safe, but brightness may cause blink and aversion |
|
3b |
> 5 – 500 |
significant eye damage may occur |
|
4 |
> 500 |
serious irreversible damage |
|
Type of Product |
Class of Laser |
|
pointing device |
1 to 3a |
|
medical or surgical lasers |
3b or 4 |
|
industrial cutting |
4 |
|
military |
4 |
Robertson et al tested laser pointers of Class 3a with exposures of up to 15 minutes in 3 patients (don't try this at home!) and found that neither acute nor delayed retinal damage occurred. This indicates that a brief, transient exposure to a Class 3a laser would be unlikely to cause ocular damage.
For class 3b and 4 lasers, proper laser protection is required. For lower power lasers sufficient eye protection may be sufficient. High powered lasers require eye, skin and additional protection, depending on the power, site exposed and extent of exposure.
Specialty: Ophthalmology
