Optometry is a health care profession that involves examining the eyes and applicable visual systems for defects or abnormalities as well as the correction of refractive error with glasses or contact lenses and treatment of eye diseases.

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 significant training in the diagnosis and management of ocular disease, in most of the countries of the world, where the profession is established and regulated.

Optometrists (also known as doctors of optometry in the United States and Canada, by a higher degree in the United Kingdom and worldwide for those holding the O.D. degree) are health care professionals who usually provide primary eye care through comprehensive eye examinations. They diagnose and manage various vision abnormalities including refractive errors as well as various eye diseases. Being a regulated profession, an optometrist's scope of practice may differ depending on the location. Optometrists typically work closely together with other eye care professionals such as ophthalmologists (specialists) and opticians to deliver quality and efficient eyecare to the general public.