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 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 higher degree in the United Kingdom and worldwide for those holding the O.D. degree) are health care 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 (i.e those requiring certain surgical interventions) are referred out to relevant medical professionals for proper care, more commonly to ophthalmologists who are physicians that specialize in tertiary 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.