To the Editor.
—Dr. Lowe has evolved a theoretical framework to support the concept that cholinergic blocking agents, such as atropine, produce a far greater incidence of post-iridectomy angle closure than do adrenergic mydriatics. However, Mapstone believes that the theoretical and mathematical assumptions made by Lowe concerning the mechanics of angle closure are not valid.1 Our clinical work lends support to Dr. Mapstone's views.There is little doubt that cycloplegics reduce outflow facility and elevate intraocular pressure in susceptible eyes.2,3 There can be no question that this phenomenon can occur in the absence of angle closure.4 These observations, when added to Dr. Lowe's findings that post-iridectomy angle closure or pressure elevation was not generally found with adrenergic agents, lends further support to our studies.5 Dr. Lowe's findings of post-iridectomy angle closure by iris crowding would be applicable in cases of plateau iris. In evaluating over 100
Harris LS. CYCLOPLEGIC PROVOCATIVE TESTING-Reply. Arch Ophthalmol. 1969;82(2):294-295. doi:10.1001/archopht.1969.00990020296030