XEN Gel Implant

Abstract

Among all the novel glaucoma surgical devices, the XEN Gel Implant (Allergan plc, Dublin, Ireland) is the only one which uses an ab-interno approach to drain aqueous to the subconjunctival space, similar to conventional filtration surgery. Most MIGS procedures target the Schlemm’s canal and the collector channels which can be difficult to locate. The patency of the downstream drainage system cannot be accurately assessed and the episcleral venous pressure cannot be routinely measured, leading to unpredictable surgical outcomes for trabecular bypass surgery. In contrast, subconjunctival aqueous drainage is more effective at lowering the intraocular pressure, as is evidenced by the efficacy of trabeculectomy which has a long track record. The main advantages of the XEN Gel Implant over other filtering procedures include its less invasive surgical procedure and the favorable safety profile, fast visual recovery, and short surgery duration, rendering this implant particularly suited for patients who are unable to tolerate a long surgical duration or a delayed visual recovery. Although designed as a stand-alone procedure, XEN implantation can be combined with phacoemulsification in patients with concurrent cataract. Although its pressure-lowering ability appears to be superior to trabecular bypass and suprachoroidal MIGS devices, there are surgical nuances which can be difficult to master and the pre- and postoperative management is critical in the success of the XEN Glaucoma Treatment System.