Surgical iridectomy involves making an opening in the rim of the iris, which allows fluid (aqueous humor) to flow between the anterior chamber, the front part of the eye, and the area behind the iris, the posterior chamber. This new route decreases pressure in the eye by allowing the normal flow of fluid through the eye and prevents sudden pressure buildup.

Because of the development of laser iridotomy, surgical iridectomy is rarely done today. However, it may be used for people who continue to have high pressure in their eyes after having a laser iridotomy. See laser iridotomy in the Surgery section of the topic Glaucoma for more information.