Why will my eyesight get worse?

Question

When I was in junior high school, I had a really good eyesight. But half a year later, I got so bad that I couldn't see anything without glasses. I want o improve my eyesight. 

Answer 1

Read by excellent light. Don't strain your eyes. Take frequent breaks when you study, every 5 minutes maybe. Practice looking outdoors and focusing on things far away, so that you won't become near-sighted.

Answer 2

you need glasses or contacts to improve your eye sight.  

Answer 3

I really am not too sure!