I've worn glasses (and/or contact lenses) for 40 years. The last four years it has been glasses only. Last year I went in for an exam and my left eye changed, the dr. said it was a small change but enough that I ordered new glasses as well as a pair of prescription sunglasses (a first for me). When I tried on the glasses I went on and on to the woman who does the glasses about how big a difference it felt, how it was going to take so much time to adjust, etc. The sunglasses seemed fine to me but she kept insisting she needed to send them back to have them darkened. I finally agreed and left the sunglasses with her but took the eyeglasses home. I didn't dare drive in them b/c the change was too great. I kept trying to wear them but couldn't and was nervous about driving in them. I thought, boy, I really am getting old because I used to adjust so quickly to changes like this. Well, the sunglasses finally came back and I picked them up. I drove in them. They felt fine. Finally, one day it dawned on me, (DUH!) why are the sunglasses not bothering me a bit but I'm totally avoiding wearing the new eyeglasses? (I had continued wearing the old ones.) The Rx should be the same! When I called her to complain (which I had complained again when I picked up the sunglasses) she said I just needed to adjust to them but finally agreed to check my chart. The had filled the glasses a complete power higher on the left eye!! No wonder I couldn't adjust.
Moral of my story, are you sure it's the correct prescription? and they are adjusted on your face properly (that can make a difference, too). Sorry to rant, I was pretty upset that she hadn't listened to me when I was complaining in the first place, although I do realize that they probably get a lot of complaints and that some times it really is just a matter of adjusting to a new prescription.