IR lasers, too. Your pupils won't contract because they don't see the light, and a lot of damage can be done very quickly. You might not notice it immediately either, because your brain can paper over small bits of retinal damage to maintain a complete image, like it does with your ocular nerve blind spots.

Lasers are super cool, but I wouldn't DIY one unless I could keep it in a goggles-only room with interlocks on the door to cut power.