You may hear the expression the “3 O’s”
Optician – A non-medical, non-doctor, vocation involved with making eyeglasses and all aspects of eyewear.
Optometrist – A doctor capable of performing all medical eyecare to the external areas of the eye and surrounding parts. May also perform refraction or Rx determination.
Ophthalmologist- A MD or medical doctor who is also a specialist in the care of eyes. They can perform all medical eyecare to the external and internal parts of the eye and surrounding parts. May also perform refraction or Rx determination