Workplace Eye Injury

I am wondering whether I have a case. Last year I worked as a substitute teacher in grades pre-k through 6th grade. Also, from time to time I taught gym. One day when I was teaching gym I got hit in the face with a basketball. I was okay at the time. I just brushed it off. But, now this month I found out when I went to get my driver's license that I could not see out of left eye. After going for eye appointment and seeing specialist I found out some new blood vessels had formed in that eye which are blocking vision in that eye. There's nothing specialist can do, not even anything experimental. Its not going to get better or worse. My regular eye doctor asked me if I had any head trauma and now that I think back on it, wondering whether this incident last school year may have caused it. I have not yet started the new school year as a sub, but wondering if I have a case against school district since I did not file claim at the time. Do I have a case? What should I do?

You insurer or the school's could be liable to cover it. You need medical records and proof and evidence of what was covered etc. and what happened.