Looking at a laser pointing onto a screen or projector should not do much if any damage to your eyes.
When looking at a laser really causes eye problems or blindness is when the laser is pointed directly into your eyes.
I've looked at lasers pointing at projectors and screens in school as well as at work and my eyes have never been damaged.
Just never point a laser into your eyes or someone else's eyes because that's when it can damage your eyesight or even blind you or the person.