Tube Insertion of Ahmed Glaucoma Valve Using a Micro-incision Scleral Tunnel Technique

Abstract

We report three cases demonstrating the efficacy and versatility of the micro-incision scleral tunnel (MIST) technique, a novel method for Ahmed glaucoma valve (AGV) tube insertion. MIST is characterized by its small incision, sutureless approach, anterior-to-posterior tunnel creation, and allograft-free design. The technique involves creating a scleral tunnel using a 1-mm crescent knife (Bleb Knife II), allowing for secure tube placement into the anterior chamber, ciliary sulcus, or vitreous cavity. Case 1 involved a male patient in his 70s with primary angle-closure glaucoma, where the tube was inserted into the vitreous cavity. Pars plana vitrectomy was combined, achieving an intraocular pressure (IOP) of 6 mmHg without medication at three months postoperatively. Case 2 described a male patient in his 70s with secondary angle-closure glaucoma due to iridocyclitis, where the tube was inserted into the ciliary sulcus. Postoperatively, the IOP was reduced to 7 mmHg without medication at three months. Case 3 was a male patient in his teens with Axenfeld-Rieger syndrome-associated glaucoma, who underwent anterior chamber tube insertion, achieving an IOP of 8 mmHg with two medications at eight months postoperatively. In addition, postoperative anterior segment findings for the other two cases were presented. These cases demonstrate that MIST simplifies surgical procedures, eliminates the need for suturing, and achieves effective IOP control. The flexibility and promising outcomes of MIST suggest its potential as an alternative technique for tube insertion in allograft-free glaucoma tube shunt surgeries.