Optometrists are healthcare professionals who provide primary vision care ranging from sight testing and correction to the diagnosis, treatment, and management of vision changes. An optometrist is not a medical doctor. An optometrist receives a doctor of optometry (OD) degree after completing four years of optometry school, preceded by three years or more years college. The history of optometry can be traced back to the early studies on optics and image formation by the eye. The origins of optometric science (optics, as taught in a basic physics class) date back a few thousand years BC as evidence of the existence of lenses for decoration has been found.