Abstract
The PRESERFLO® MicroShunt (Santen Pharmaceutical Co. Ltd., Osaka, Japan), formerly called the InnFocus MicroShunt®, is a trans-scleral device that shunts aqueous humour from the anterior chamber to a filtering bleb under the conjunctiva and Tenon’s capsule. Manufactured from an inert biocompatible material called poly(styrene-block-isobutylene-block-styrene), or ‘SIBS’, the device elicits minimal foreign body reaction and inflammation; potentially reducing the risk of bleb-related fibrosis and failure. The MicroShunt is 8.5 mm long with a 70 μm lumen and is designed to minimize hypotony based on the Hagen–Poiseuille equation. Inserted via an ab-externo approach, the MicroShunt eliminates the need for creation of a scleral flap, sclerostomy, iridectomy, scleral flap suturing and postoperative suture lysis. Clinical trials show promising results with the MicroShunt achieving intraocular pressure reduction approaching that of trabeculectomy, the current gold standard for treating refractory glaucoma.