New ab interno technique for removal of iris-embedded EX-PRESS shunt and chronic eye pain caused by shunt malpositioning.

The EX-PRESS shunt (Alcon Laboratory) is a stainless steel implant designed to shunt aqueous from the anterior chamber to the subconjunctival space.Thedevice isplacedundera scleral flap,with the lumenideallypositionedparallel to the iris. A properly positioned EX-PRESS shunt creates acontrolledcommunicationbetween the anterior chamber and the bleb.1 Several shunt-specific complications havebeendescribed elsewhere, includingblockage, extrusionorexposure,andanteriordislocation.2-4 Inadditiontothese complications, malpositioning of the shunt can occur but, to our knowledge, has never been reported as a source of debilitating chronic eye pain requiring shunt removal. We describe a new technique for gonioscopy-assisted ab interno removal of an EX-PRESS shunt. We also report findings in a patient with severe eye pain due to indentation and chafing of the superior iris stroma caused by an iris-embedded shunt. The patient’s eye pain resolved completely after successful ab interno removal of the malpositioned shunt. In a second patient, the ab interno techniquewasused to removeanonfunctioning shuntduring another glaucoma procedure. Report of Cases