Originally Posted by
The_Doctor
Class 2, 1mW of visible light is eye-safe, but take care with certain conditions. Don't view the spot through a strong hand magnifier, and don't stare down the business end, directly into the beam. If you catch a glancing flash, even off a flat shiny metal surface, you'll be ok. You're right to be cautious because stronger beams capable of damage may not be noticed when causing it.
Laser power classes relate to illuminated area, so strength per unit area is what matters rather than total power. It's often complex, but worth an initial look on Wikipedia concerning laser classes. I don't think anyone gets it all in one go, first time, so if you're workign with any kind of laser it pays to revisit the subject, take in whatever you can each time.