A DIAGNOSTIC-APPROACH TO ANISOCORIA

The condition in which the pupils differ in size is referred to as ani socoria. This physical examination finding can be normal (dynamic cont raction) or can indicate an underlying ocular or neurologic abnormalit y. Because anisocoria can be more pronounced in either bright light or dim light, pupillary size and symmetry should be assessed in various light conditions. Localization of the cause of anisocoria helps the cl inician to formulate a diagnostic plan and a list of diagnostic differ entials. The first step in approaching a case of anisocoria is to rule out primary ocular causes; after this is done, the clinician can purs ue a neurologic cause. A few clinical observations can facilitate clas sification of a neurologic cause of anisocoria into one of the three m ajor divisions: sympathetic efferent, pupillary afferent, or parasympa thetic efferent. With the aid of an algorithm, this article presents a problem-oriented diagnostic approach to anisocoria.