Doctor or Not?!

Let's play the game of "Doctor or Not!?" yayyy

Psychiatrist.  Psychologist.  I can never remember which is which.  One's a medical doctor, the other is a therapist. 
Hmm.  I try to remember by thinking, podiatrist, dermatologist--those are both doctors.  That didn't help.  Gynecologist.  Geriatrist.  Neurologist.  Still no help.
The truth is, there are a lot more -ologist words in the world than -iatrists, but what's the difference??

Dictionary says...
-ology refers to the science or study of something
-iatry indicates healing or medical treatment

Ok.  So etymologically, they could both be doctors, but in this case the psychiatrist is the doctor and the psychologist is not.

What about optometrist and opthalmologist and optician?  Opto- obviously means sight from Ancient Greek.

Optometrist - someone licensed to practice optometry (which is the practice of examining the eyes). -metrist is obviously someone who measures, so optometrist literally= someone who measures sight

Opthalmologist - a doctor who practices opthalmology (which is the branch of medical science dealing with the anatomy, functions, and diseases of the eye), so opthalmologist literally= scientist who studies sight

Optician - a maker or seller of optical glass, so optician literally= someone who specializes in sight

So in this case the opthalmologist is the doctor and the optometrist and the optician are not.

Thanks for playing.