Well, yes, it is possible to have eye strain if you watch on the ipad mini screen. And according to some researches, it is normal to have some eye problems if you look at ipad screen for a long time. First, you should know that when you look at ipad screen for a long time, it will just make your eyes focus on the small point. And that can just increase eye pressure and then, your eyes will be stressed, leading to eye strain. What is more, it can put stress on the eye muscles and the facial and scalp muscles, causing pain and headache, even red eyes. So just be careful about it, and it can be harmful for your eyes.