There are also ophthalmologists. That requires at least 8 years of post undergraduate training in the US. 3 years which is surgical residency.
Do you also have 'opticians' as well as ophthalmologists and optometrists?
Yes. Though they are not eye doctors in any meaningful sense of the word. It requires a pretty straightforward certification while the other two require years of post graduate training.
I believe opticians are the people that measure your PD adjust frames.