Any Intense light can harm.
Lasers are intense light.
Training required for class 3-4.
CLASS 3, 3R, 3B and 4 REQUIRE EHS-4820 TRAINING BEFORE USE
There are class 3 and 4 lasers at Hopkins. Most of them are sealed in the confocal scopes, but not all. Signs are posted in areas where these potentially dangerous lasers are used.
The laser pointers we are all familiar with are considered class1 devices.
These can still cause harm if abused, but do not normally present a threat.
ANY intense light, whether from a LED flashlight, looking directly at the sun, or any laser, can cause harm.
-> Laser pointers are a source of intense light.
Therefore looking directly into the beam for a length of time can cause temporary to permanent harm.
Never point a laser pointer at someone or an animal's eyes (not even your cat). Lasers are NOT toys, in spite of how they are marketed.
You may have heard of pilots on planes suffering disorientation from pranksters (or terrorists) purposely doing this.
We have all been in a seminar where the speaker cannot let go of the button and swings the pointer around the room randomly.
(if you witness this, take the laser pointer away from them and hand them a stick instead)
(you would think everyone ducking under their chairs would be a clue).
This page is listed under Hazards, but of course lasers are useful as well. A small amount of common sense will allow safe use.