Plateau iris is one of the most common angle-closure glaucomas presenting in younger patients. This condition is characterized by closing of the anterior chamber angle secondary to a large or anteriorly positioned ciliary body that mechanically alters the position of the peripheral iris in relation to the trabecular meshwork.
In plateau iris configuration, the pars plicata may be large and anteriorly positioned, mechanically positioning the peripheral iris against the trabecular meshwork. In addition, the iris root is inserted anteriorly on the ciliary face further crowding the anterior chamber angle. The iris crowding of the angle obstructs aqueous flow via the trabecular meshwork and may lead to angle-closure glaucoma.
Except in the rare younger patients (age 20-30s), some degree of pupillary block also is present. Because a component of pupillary block may exist in patients with plateau iris configuration, laser iridotomy should always be performed as the first intervention. If the angle remains capable of closure despite a patent iridotomy, the condition is termed plateau iris syndrome.
A high prevalence of plateau iris configuration and plateau iris syndrome has been reported in relatives of patients with plateau iris syndrome. An autosomal dominant inheritance pattern with incomplete penetrance has also been suggested. 
The exact prevalence of plateau iris is unknown. A 2016 study found that one third of eyes with primary angle-closure glaucoma had plateau iris.  In another report, it accounted for more than half of recurrent angle closure cases in young patients.  The diagnosis of plateau iris should be suspected when angle closure occurs in patients who are young or myopic and when angle narrowing persists despite iridotomy.
In a study from Singapore, plateau iris was found in about a third of primary angle closure suspects older than 50 years of age after laser iridotomy.  Another study found that 20% of Japanese patients with primary angle closure after laser iridotomy had plateau iris based on ultrasound biomicroscopy. 
Plateau iris is an important cause of angle-closure glaucoma in patients younger than 50 years.
Plateau iris is seen most commonly in women.
Patients with plateau iris usually are younger than those with primary angle-closure (relative pupillary block) glaucoma.
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