How long will it take for my eye sight to stabilize?

I have diabetes 2. I was recently diagnosed. One of the reasons I realized I had a problem is that my eye sight was blurry and I had just purchased new gles that were not providing clear vision. I understand that the cornea becomes misshaped with the sugar and that is what causes the vision to be bad. How long would it take for the eye sight to either return, or just stabilize so I can order new gles?