Well, yes, it is normal to have blurry vision if you look at ipad screen for a long time. Generally speaking, when you look at ipad screen for a long time, it will just make your eyes focus on the small point. In a long time, it will just make your eyes have high eye pressure. In that way, your eyes will be stressed, leading to eye strain. And then, it can put stress on the eye muscles and the facial and scalp muscles, causing pain and headache, even red eyes, and blurred vision. So you should not look at the small screen for a long time, and it can be harmful for your eyes.
It seems that you are quite addicted to Ipad, actually, I also find it quite amazing and could give you a lot of pleasure. However, as you can see, some application especially games would make your eyes very tired if you keep playing them, and once you have an eye strain , or constant use of it, you would have blurred vision. Of course it is normal for you to have that feeling. But if the problem keeps going, you should have an eye exam to see where went wrong.
After you use the Ipad for a long time, you may get tired at the eyes because of the tiredness of the eye nerves. You could find that the glare screen may stimulate your eyes. You should not do this often. Or else, your eyes may get the short sighted problems. You should also use some eye drops to release the eyes.