The EX-PRESS Glaucoma Filtration Device (Alcon; Fig 17-13) is a shunt used in a variation on trabeculectomy. It was initially designed to be a stand-alone subconjunctival device inserted at the limbus. However, a high incidence of postoperative hypotony and erosion of the device through the conjunctiva necessitated a change in the surgical approach. The current technique for implantation follows steps similar to those used in trabeculectomy. The key difference is that the surgeon inserts the device underneath a partial-thickness scleral flap instead of removing a corneoscleral block of tissue. In addition, a peripheral iridectomy is not performed with the EX-PRESS shunt.
Several retrospective and prospective randomized trials comparing trabeculectomy with the EX-PRESS device to standard trabeculectomy have shown similar long-term IOP results, although vision recovery may be faster with the shunt than with trabeculectomy alone. Complications are similar, including hypotony, choroidal effusion, and infection. Device extrusion or migration is a rare complication that requires removal. EX-PRESS shunts are magnetic resonance imaging (MRI)-safe up to 3 Tesla.
Figure 13-17 Schematic illustration of an EX-PRESS shunt placed under a scleral flap. GFD = glaucoma filtration device.
(© 2020 American Academy of Ophthalmology.)
Gonzalez-Rodriguez JM, Trope GE, Drori-Wagschal L, Jinapriya D, Buys YM. Comparison of trabeculectomy vs Ex-PRESS: 3-year follow-up. Br J Ophthalmol. 2016;100(9):1269–1273.
Netland PA, Sarkisian SR Jr, Moster MR, et al. Randomized, prospective, comparative trial of EX-PRESS glaucoma filtration device versus trabeculectomy (XVT study). Am J Ophthalmol. 2014;157(2):433–440.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.