Im 25 years old and Iam currently wearing glasses.  I am nearsighted and the glasses that I wear have a grade of 300.  I started having problems with my eyesight when I was in 3rd grade and that's when I had my first set of glasses.  I tried using contact lens but everytime I buy a new set, my vision keeps getting worse.  Is there any medicine or procedure that I can undergo to restore my eyesight to 20-20?  And once I get my eyesight restored, what are ways that I could maintain that 20-20 vision and prevent me from going back to glasses?