A New and Easier Approach to Preserflo MicroShunt Implantation

PRESERFLO™ MicroShunt is a new minimally invasive glaucoma surgical (MIGS) device, implanted with an ab externo approach, which drains the aqueous humor to the subconjunctival space. It has been designed as a safer and less invasive approach for treating medically uncontrolled primary open-angle glaucoma (POAG) patients. The classic way of MicroShunt implantation involves different key steps, which includes creating a small scleral pocket with a 1mm blade; passing a 25-gauge (25G) needle through the scleral pocket into the anterior chamber (AC); and subsequently flushing the stent with a 23-gauge (23G) thin-wall cannula. However, sliding the needle into the scleral pocket can create false passages, thus making the device's threading more difficult. The purpose of the current paper is to propose a simplified implantation approach. Our method proposes to make the scleral tunnel by using directly the 25G needle and, at the limbus, this 25G needle is used to slightly depress the sclera and enter into the AC. The MicroShunt is subsequently assembled on a 23G cannula mounted on a 1mL syringe. The syringe can then be used to flush the device. Outflow can thus be confirmed immediately by seeing drops of aqueous humor leaking from the external opening of the stent. This new approach may have different potential advantages, such as better control of the site of entry, avoids wrong passages, reduces or eliminates the risk of aqueous humor sideway flow, facilitates a parallel path to the iris plane, and it is faster.