Eye Damage from laptop screen?

Is it possible to permantently damage your eyes from staring at the computer screen too much?

Lately my eyes have been playing wierd tricks on me, I see things move in the corner of my eye that aren't there, or I'll see colored spots randomly. I've noticed it comes after I've been up real late using the computer (it's happening right now). However I also notice these problems during the day, away from my computer screen. I'm begining to think that my eyes are being damaged by my laptop.

Does anyone else get things like this from watchign their computer screen? Is this something to be worried about?