Keith-Wagener-Barker classification system [Norman M. Keith, Canadian physician, b. 1885; Henry P. Wagener, American physician, b. 1890; N.W. Barker, 20th-century American physician] , a method of classifying the degree of hypertension in a patient on the basis of retinal changes. The stages are group 1, identified by constriction of the retinal arterioles; group 2, constriction and sclerosis of the retinal arterioles; group 3, characterized by hemorrhages and exudates in addition to group 2 conditions; and group 4, papilledema of the retinal arterioles.
