Well, of course, it can cause permanent damage to your eyes, if your watch computer too much, for it can lead to eye strain, and then can cause many eye diseases. Generally speaking, if you have got eye strains, it can lead to many long term effects. For example, it can put stress on the eye muscles and the facial and scalp muscles, causing pain and headache. And what is worse, it can lead to making your vision become worse. And finally, you have to wear glasses. In a long term, eye strains can make your eyes become dry and lead to dry eyes, and watery eyes. So you should not watch computer in a long time. And just keeping your eyes be in a good rest is very essential.