depends on the grade, the wee ones are low power and not so bad, but the more powerful ones (including some sights/pointers and surveyors lasers) can cause permanent retinal damage...you don't notice how bad it is either because the eye isn't all that sensitive to red light...... it still does the damage though. (We see green better...... throw back to when we had to be able to tell tigers and trees apart at dusk).