Surgical Technique for Pars Plana Ahmed Glaucoma Valve Implantation in Advanced Glaucoma: The Upside-Down Technique.

PRCIS Ahmed glaucoma valve implantation using the upside-down technique resulted in an aqueous humor outflow pathway, occurring primarily on the scleral side and secondarily on the conjunctival side, and was effective in treating refractory glaucoma. PURPOSE To describe the Ahmed glaucoma valve (AGV) surgical technique, which results in changes in the primary aqueous humor outflow pathway to the scleral side (upside-down technique), and to evaluate the clinical effects and distribution of bleb fluid after surgery in patients with refractory glaucoma. PATIENTS AND METHODS In this retrospective study, the upside-down technique was used for pars plana AGV implantation in 10 eyes of 10 patients with refractory glaucoma. Surgical success was defined by complications, intraocular pressure (IOP), the glaucoma medication score, and bleb fluid distribution determined by magnetic resonance imaging (MRI). RESULTS Postoperatively, there were significant reductions in the IOP and medication score at 23 and 27 months, respectively (P<0.05). Although a transient hypertensive phase was observed in seven patients, it was controlled without ocular massage and additional surgery. A patient who had suprachoroidal hemorrhage during surgery lost light perception 7 months after the surgery, and another patient developed hypotony at 3 and 4 months after surgery, which spontaneously improved during subsequent examinations. MRI showed that the double bleb layer adjacent to the endplate tended to have more bleb fluid on the conjunctival side than on the scleral side facing the outlet (n=8; 1-29▒mo after surgery). CONCLUSIONS Pars plana AGV implantation using the upside-down technique was a relatively effective alternative to manage inadequate IOP control in patients with refractory glaucoma.