The location of repository corticosteroid after subtenon injection was determined in 24 patients with macular edema associated with uveitis or anterior segment surgery. Standardized A-scan and B-scan echography were performed immediately before and after each injection. Localization was compared after subtenon injection in either the superior or inferior temporal quadrants. Echography showed that corticosteroid was deposited within the subtenon space over the macula in 11 of 24 cases. The therapeutic response manifested by improvement in macular function may be related to the proximity of the corticosteroid to the macular area. Lack of therapeutic response to repository corticosteroids may be because of placement at a site relatively far from the target zone.