Except Optometrists train on systemic disease as well so your facts are wrong. Dental school is very similar to Optometry school. We take anatomy, biochem, physiology, general and ocular pharmacology, histology, microbiology and more.
Then in 3rd and 4th years we are basically like residents. For example I am going to a VA Hospital, a secondary and tertiary care private center and West Point Army Hospital for my 3 out rotations.
Even the entrance exam to Optometry school is the same as Dental school except no perceptual ability and we have an extra physics section.
Hope this clears up some confusion.
Yes, or we can hire MDs. Works either way in many states.