An eye examination is a series of tests performed to assess vision and the ability to focus on and discern objects. It also includes other tests and examinations pertaining to the eyes. Health care professionals often recommend that all people have periodic and thorough eye examinations as part of routine primary care, especially since many eye diseases are asymptomatic. Eye examinations may detect potentially treatable blinding eye diseases, ocular manifestations of systemic diseases, or signs of tumours or other anomalies. A full eye examination consists of an external examination followed by specific tests.