new prescription and bad vision

I recently had an eye exam and the doctor (Dr. N) gave me a
prescription that was substantially different from my old prescription.
My vision, with or without glasses has always been pretty good yet the
new glasses made my vision slightly blurry. I went back Dr. N and he
gave me a new prescription with the same results, slightly blurry
vision.

I went to a new doctor today and he gave me a prescription much closer
to my old glasses. He looked at Dr. N's prescription and basically had
no clue as to why the doctor prescribed what he did.

This may seem like a stupid question, but should there ever be a
scenario in which new glasses make your vision worse? Could it be
possible that a new prescription might degrade one's vision yet somehow
improve it over time? This seems completely ridiculous to me but I'm
also not an eye doctor.

 

Everyone has certain theoretical vision correction ( Rx) based on the shape
of the eye, but younger people can make their eyes adapt by physically
changing the shape of the eye. When you get older, you are not able to do
that as easily, so the desired Rx is closer to the theoretical Rx. It is
usually best to not over prescribe if your eyes can adapt to a "better than
theoretical" Rx.

But bottom line is that in any profession, some are better than others, and
some are incompetent. BTW, never go to an ophthalmologist to get an eye exam
(unless you have a eye disease or some other serious eye condition). Go to
an OD (optometrist) whenever possible for your exam.