Optometry is a health care profession which involves examining the eyes and applicable visual systems for defects or abnormalities as well as the medical diagnosis and management of eye disease. Traditionally, the field of optometry began with the primary focus of correcting refractive error through the use of spectacles. Modern day optometry, however, has evolved through time so that the educational curriculum additionally includes intensive medical training in the diagnosis and management of ocular disease in countries where the profession is established and regulated. Optometrists (also known as Doctors of Optometry in the US and Canada for those holding the O.D. degree or Ophthalmic Opticians in the UK) are medical professionals who provide primary eyecare through comprehensive eye examinations to detect and treat various visual abnormalities and eye diseases. Being a regulated profession, an optometrist’s scope of practice may differ depending on the location. Thus, disorders or diseases detected outside the treatment scope of optometry are referred out to relevant medical professionals for proper care, more commonly to ophthalmologists who are medical doctors that specialize in advanced medical and surgical care of the eye. Optometrists typically work closely together with other eye care professionals such as ophthalmologists and opticians to deliver quality and efficient eyecare to the general public.
The term “optometry” comes from the Greek words ὄψις (opsis; “view”) and μέτρον (metron; “something used to measure”, “measure”, “rule”). The word entered the language when the instrument for measuring vision was called an optometer, (before the terms phoropter or refractor were used). The root word opto is a shortened form derived from the Greek word ophthalmos meaning, “eye.” Like most healthcare professions, the education and certification of optometrists is regulated in most countries. Optometric professionals and optometry-related organizations interact with governmental agencies, other healthcare professionals, and the community to deliver eye- and vision-care.
Source : https://en.wikipedia.org/wiki/Optometry