Although there are always a few bad apples in any group, your can rest assured that your optometrist is probably quite intelligent and well trained. There are only 17 optometry colleges in the United States, and the competition to get in is quite fierce, requiring excellent grades in just about everything.
Don't mistake your optometrist for a mere optician. Optometrists are trained doctors who can perform detailed eye tests and dispense eyewear prescriptions; opticians basically just sell and fit eyewear. In Great Britain, some opticians provide both services, but they're vanishingly rare in the U.S.