Contributor: Gordon K. Klintworth
Angle closure glaucoma (closed angle glaucoma) is a special type of  glaucoma  in which the anterior chamber angle is closed. It can be subdivided into primary angle closure glaucoma [glaucoma - primary angle closure] and secondary angle closure glaucoma [glaucoma - secondary angle closure]. Both types can be further classified according to the site where aqueous humor flow is blocked. An obstruction to the forward flow of aqueous humor past the lens and through the pupil towards the anterior chamber may initiate angle closure glaucoma. This can occur as a consequence of  pupillary block, ciliary body block or vitreous block. Aqueous humor outflow may be normal until the site where the iris blocks entry of aqueous humor into the trabecular meshwork. Such a blockage of aqueous humor drainage into the anterior chamber angle can result from peripheral anterior synechiae in the absence of pupillary block (as with plateau iris or a perforating corneal injury with a post-traumatic collapse of the anterior chamber). Angle closure glaucoma may be unilateral [glaucoma - angle closure unilateral].