Intermediate-term Clinical Experience With the Ahmed Glaucoma Valve Implant MORGAN C. HUANG, MD, PETER A. NETLAND, MD, PHD, ANNE L. COLEMAN, MD, PHD, SCOTT W. SIEGNER, MD, MARLENE R. MOSTER, MD, AND RICHARD A. HILL, MD ● PURPOSE: We studied the intermediate-term clinical experience with the Ahmed Glaucoma Valve implant (New World Medical, Inc, Rancho Cucamonga, California). ● METHODS: In this multicenter, retrospective case series, we studied 159 eyes (144 patients) treated with the Ahmed Glaucoma Valve with a mean  SEM (standard error of mean) follow-up of 13.4  0.7 months (range, 4 to 44 months). The mean  SEM age was 60.9  1.9 years (range, 0.1 to 103 years). Surgical success was defined as intraocular pressure less than 22 mm Hg and greater than 5 mm Hg without additional glaucoma surgery and without loss of light perception. Postoperative use of antiglaucoma medications was not a criterion for success or failure. The definition of hypotony was intraoc- ular pressure of 5 mm Hg or less in two consecutive visits. ● RESULTS: Intraocular pressure was reduced from a mean of 32.7  0.8 mm Hg before surgery to 15.9  0.6 mm Hg (P < .0001) at the most recent follow-up after surgery. The number of antiglaucoma medications was decreased from 2.7  0.1 before surgery to 1.1  0.1 after surgery (P < .0001). The cumulative probability of success was 87% at 1 year and 75% at 2 years after surgery (Kaplan-Meier life-table analysis). Postopera- tively, 24 (15%) of 159 eyes had intraocular pressure greater than or equal to 22 mm Hg. The visual acuity was improved or within one Snellen line in 131 eyes (82%). Complications occurred in 75 eyes (47%), the majority of which did not affect surgical outcome. The most common complication was obstruction of the tube, which was observed in 17 eyes (11%). Transient postoperative hypotony was found in 13 eyes (8%). ● CONCLUSIONS: The Ahmed Glaucoma Valve implant is effective in lowering intraocular pressure, and postop- erative hypotony is not commonly associated with this implant. (Am J Ophthalmol 1999;127:27–33. © 1999 by Elsevier Science Inc. All rights reserved.) G LAUCOMA DRAINAGE IMPLANTS ARE A USEFUL alternative in treating glaucomas that are resistant to medical therapy and glaucoma filtration sur- gery. 1,2 These implants have a small-caliber silicone tube that drains aqueous from the anterior or posterior chamber to an extrascleral device that maintains a fibrous pseudo- cyst through which filtration can occur. A variety of aqueous shunting devices have been developed, including open-tube and valved designs. Hypotony during the im- mediate postoperative period is a common complication associated with the open-tube implants. 3,4 Although valved implants may not completely close after initial perfusion with fluid, they do function as flow-restricting devices. 5 The Ahmed Glaucoma Valve implant (New World Medical, Inc, Rancho Cucamonga, California) directs aqueous flow through the silicone tube and between two thin silicone elastomer membranes in a tapered chamber. The initial clinical experience with this implant indicated that hypotony and its attendant complications during the immediate postoperative period were less common than reported with other glaucoma drainage devices. 6 Our purpose in this study was to investigate the short- and long-term clinical effectiveness of the Ahmed Glaucoma Valve implant in a multicenter review of patients with glaucomas refractory to other treatments. See also pp. 34 – 42. Accepted for publication Sept 24, 1998. From the University of Tennessee, Memphis, Tennessee (Drs Huang and Netland); Jules Stein Eye Institute, Los Angeles, California (Drs Coleman and Siegner); Wills Eye Hospital, Philadelphia, Pennsylvania (Dr Moster); and University of California, Irvine, California (Dr Hill). Supported in part by Research to Prevent Blindness, Inc, New York, New York. The authors have no proprietary interest in the Ahmed Glaucoma Valve implant. This study was presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology in Fort Lauder- dale, Florida, May 12, 1998. Correspondence to Peter A. Netland, MD, PhD, Department of Ophthalmology, University of Tennessee, Memphis, 956 Court Avenue, Memphis, TN 38163; fax: (901) 448-1299; e-mail: pnetland@mail. eye.utmem.edu © 1999 BY ELSEVIER SCIENCE INC.ALL RIGHTS RESERVED. 0002-9394/99/$20.00 27 PII S0002-9394(98)00394-8