Optometrists and Prescriptions
My impression is that vision exams are at least somewhat subjective. Maybe more so for some people; I've had at least 2 optometrists tell me that I wasn't taking their tests well (answering consistently).
Finding someone who wrote me a prescription I liked right off worked much better for me than trying to work with optometrists whose prescriptions I didn't like.
I found him by asking the best optician I'd found for a recommendation. I've also seen people suggest asking an optical lab or optometry school for recommendations.
What didn't didn't work for me was trying to get optometrists whose prescriptions I didn't like to write very different ones (especially since it was hard to explain well what was bothering me).
Another thing I believe (but am not sure of) is that distance glasses can be a lot less exact before you notice it, but that close glasses have a lot less leeway. That might not be true for everyone, but was for me.
Optometrists and opthomologists write prescriptions differently (see sections 2.1 through 2.3 on this page). You should always get and keep copies of all your prescriptions and understand what they say.
My feeling is that it's worth whatever it takes to find an optometrist you like.