Thank you very much for your replies!
I'm actually aware of the importance of brightness adjustment, that is why I always check for these kind of things (and also angle adjustment) in the displays I buy.
I started using preservative free tears and adding omega 3 to my diet.
I searched the web days ago for reviews about computer glasses, though it doesn't seem "real", but people are very satisfied, and it's said that they do help in my kind of situation:
I'm asking for your professional opinion, I mean by coloring the lenses in yellow tint and putting some filtering layers on them, DO really help?
It could be related to dry eyes, eye strain from contrast/brightness (per TurtleJoe), or latent hyperopia or early presbyopia. First, you need to educate yourself more about dry eyes. Read the other related posts. Second, you may try preservative free tears (OTC various brands) and second add lots of omega 3's to your diet. Finally, you need a good eye exam and preferably dilated or cycloplegic refraction to check for latent hyperopia (just ask the Eye MD about this).
Timothy D. McGarity, M.D.
It amazes me that the majority of PC users are unaware of the need to reduce the contrast and brightness of Monitors to reduce eyestrain and morning headaches. Laptops I have seen do not allow adjustment short of tilting the screen slightly forward or backward to allow same visual effects. Try it you will like it.