Another name of lazy eyes is Amblyopia. And lazy eyes often occur to child when one of their eyes does not develop as they should be. As far as i know, lazy eyes does not related to a concussion. So, don't be nervous. You are Ok. But if you feel really headache, dizziness, vision blurry from the hit, you'd better see a doctor and check your head in case any damages to your brain. Good luck.
Well, this usually happens to children coz children are not so strong in any parts of their body. First of all, you should know that a concussion may cause some side effects to eye muscle function. It means that you may not only get a lazy eye but also some other vision problems such as blurry vision, burning eyes and so on. In this situation, only medication treatment can be the most effective. Eye exercise no longer works! Since your eye muscles are damaged, how can you count on your eye muscles to work well? Anyway, for your eyes' s sake, you had better go to a professional doctor as soon as possible.