An
M.D. who specializes in
Eyes and their disorders. Known as a
tertiary care specialist, patients need to be refererred to them by a regular
doctor.
Ophthalmology was the first medical specialty to branch off of General Practicioner.
Sometime early 1900's, there were doctors. No specialists then, they did everything. Then some became very good at diagnosing disorders of the eye. So they pretty much dropped their general practice and just handled referrals and eye cases. The first eye doctors came about, and medical schools later tailored their curricula to accomodate the specialties as others, such as obstetrician, seceded from the title of regular doctor and primary care.
Nowadays there are Superspecialsts who only specialize in a more narrow branch, such as only the retina. Funny how they make more money than just vanilla Ophthalmologists. There used to be an old joke about one eye doctor only treating the left eye, never the right. It stopped being funny and more of a reality in the 1950's
An Ophthalmologist can do everything an optometrist and optician can't do. Training requires 4 years of college, 4 years of medical school, 1 year of internship, and at least 2 years of residency. A little longer to be board certified.