Blunt injury to the globe may result in traumatic mydriasis or, less commonly, miosis. Traumatic mydriasis is often associated with iris sphincter tears that can permanently alter the shape of the pupil. Miosis tends to be associated with anterior chamber inflammation (traumatic iritis; see the following section). Pupillary reactivity may be sluggish in both situations. Cycloplegia is essential to prevent formation of posterior synechiae.