Iris retraction syndrome
D. Schedule combined phacoemulsification-vitrectomy surgery
Iris retraction syndrome is a rare entity initially described by Campbell1 in 1984. The proposed pathogenesis is that the retinal pigment epithelium (RPE) excessively absorbs aqueous humor and acts as a pump in the posterior segment. This overabsorption could be secondary to exposure of RPE through a peripheral retinal tear, but retinal breaks, although present in most cases, are not always noted.2 The misdirected flow of aqueous humor can lead to an inversion of the pressure gradient between the anterior and posterior chambers. This in turn can lead to a reverse pupillary block and its associated proinflammatory consequences.3 The associated exudative retinal detachment could be related to the absorption of the aqueous humor by the RPE toward the suprachoroidal space and to inflammation.4 The aim of the treatment is, one the one hand, to lyse posterior synechiae between the iris and the lens and, on the other hand, to drain the subretinal fluid and to treat the tear—when found—through pars plana vitrectomy. In some cases, medical treatment alone with topical atropine and steroids may be sufficient.2 Peripheral iridotomy (choice A) might be a dangerous option, as the iris is wedged to the lens and would not modify the misdirection of the aqueous humor flow. Sclerotomy (choice B) to drain fluid likely would not be appropriate, as the initial mechanism is not related to uveal effusion. Corticosteroid therapy (choice C) typically would not be useful, as the primary cause is not inflammatory.1,4 Iris retraction syndrome requires surgical management (choice D) to stop misdirected flow of aqueous humor toward the posterior segment. A topical treatment combining atropine and corticosteroids can be prescribed while awaiting surgery.