Using the computer, good points and bad points

I don't like using comruters very much.　Because they are bad for eyes, so they may cause failure of eiesight if we use too much. And they may make our posture bad. And there is a risk of our being invaded our privacy by using comuters. But I think there are good points on compouters. Coumputers supply us with a lot of information. And we can whatch movies and read news. In addition to it we write. We can add words without rewriting.Now, computers are necessary for our lives(90words).