I have a weird situation with my vision, where I wore contacts for many years. I was on my last pair and one popped out and I had to wear just one for like 4 weeks before more came. And I noticed that my contact free eye had adjusted itself to see as well as the eye that was using a contact lens. So when I got more lenses I decided to alternate back and fourth for about 3 weeks between each eye. and now I see ten times better than I use to and I don't wear contacts any more at all.
My doctor was astounded and he said I actually re-trained my eyes to focus correctly.