The plateau iris component of primary angle closure glaucoma: developmental or acquired.

Primary angle closure glaucoma has been called the most common form of glaucoma in the world, and the leading cause of bilateral blindness. Pupillary block is felt to be the main mechanism of outflow obstruction in this condition. Recent advances in morphologic assessment of angle closure, specifically by means of ultrasound biomicroscopy, have revealed that plateau iris in eyes with angle closure glaucoma is more common than had previously been thought. The most characteristic finding in this disease is thicker and more anteriorly positioned lens. This induces the pupillary block that relives by laser iridotomy. Residual angle closure after laser iridotomy is due to the plateau iris. Peripheral iridoplasty, the standard treatment of plateau iris, tights the peripheral iris and opens the angle but has no effect on the ciliary processes configuration. The ciliary processes are positioned posteriorly after lens extraction but dose not disappears completely. Considering these facts we hypothesized that the plateau iris in primary angle closure glaucoma is a developmental entity that reaches to a critical stage with aging owing to the thickening and forward movement of the lens. Cataract surgery deeps the anterior chamber, widens the irido-corneal angle and reposits the ciliary processes posteriorly, so it can prevents synechia formation and progressive lens-induced angle narrowing and plateau iris progression, the acquired component, with aging.