[bonoboTP]

Note that "optometrist" is distinct from "ophthalmologist", which is the actual eye doctor. The optometrist job is only about fitting glasses and contacts for near/farsightedness, while ophthalmologists can treat all manners of eye diseases.

And the final form of dentists, oral-maxillofacial surgeons are an all in one and have to study general medicine, surgery and dentistry.

[razakel]

An optician fits lenses, an optometrist measures your vision (and can refer you to an ophthalmologist if they spot something unusual).