title: The Ahmed Versus Baerveldt Study: Five-Year Treatment Outcomes.
abstract: To compare 2 frequently used aqueous shunts for the treatment of glaucoma.
  
  
  
  International, multicenter, randomized trial.
  
  
  
  Patients aged 18 years or older with uncontrolled glaucoma despite maximum tolerated medical therapy, many of whom had failed or were at high risk of failing trabeculectomy.
  
  
  
  Eligible patients were randomized to receive an Ahmed-FP7 valve implant (New World Medical, Inc, Rancho Cucamonga, CA) or a Baerveldt-350 implant (Abbott Medical Optics, Inc, Santa Ana, CA) using a standardized surgical technique.
  
  
  
  The primary outcome was failure, defined as intraocular pressure (IOP) outside the target range (5-18 mmHg) or reduced <20% from baseline for 2 consecutive visits after 3 months, severe vision loss, or de novo glaucoma surgery. Secondary outcomes measures included IOP, medication use, visual acuity, complications, and interventions.
  
  
  
  A total of 238 patients were randomized; 124 received the Ahmed-FP7 implant, and 114 received the Baerveldt-350 implant. Baseline characteristics were similar between groups. Mean preoperative IOP was 31.4±10.8 mmHg on 3.1±1.0 glaucoma medications. At 5 years, the cumulative failure rate was 53% in the Ahmed group and 40% in the Baerveldt group (P = 0.04). The main reason for failure in both groups was high IOP, and the cumulative de novo glaucoma reoperation rate was 18% in the Ahmed group and 11% in the Baerveldt group (P = 0.22). Hypotony resulted in failure in 5 patients (4%) in the Baerveldt group compared with none in the Ahmed group (P = 0.02). Mean IOP was 16.6±5.9 mmHg in the Ahmed group (47% reduction) and 13.6±5.0 mmHg in the Baerveldt group (57% reduction, P = 0.001). Mean medication use was 1.8±1.5 mmHg in the Ahmed group (44% reduction) and 1.2±1.3 mmHg in the Baerveldt group (61% reduction, P = 0.03). The 2 groups had similar complication rates (Ahmed 63%, Baerveldt 69%) and intervention rates (Ahmed 41%, Baerveldt 41%). Most complications were transient, and most interventions were slit-lamp procedures.
  
  
  
  Both implants were effective in reducing IOP and the need for glaucoma medications. The Baerveldt group had a lower failure rate and a lower IOP on fewer medications than the Ahmed group, but had a small risk of hypotony that was not seen in the Ahmed group.
authors.affiliation: Department of Ophthalmology and Vision Sciences, University of Toronto Faculty of Medicine, Toronto, Canada.
authors.forename: Panos G
authors.initials: PG
authors.lastname: Christakis
authors.affiliation: Drs. Massaro & Kalenak SC, Milwaukee, Wisconsin.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Kalenak
authors.affiliation: Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: James C
authors.initials: JC
authors.lastname: Tsai
authors.affiliation: Department of Anesthesiology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts.
authors.forename: David
authors.initials: D
authors.lastname: Zurakowski
authors.affiliation: Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kammer
authors.affiliation: Department of Ophthalmology, University of Montreal, Montreal, Canada.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Harasymowycz
authors.affiliation: Clinic of Las Condes, Santiago, Chile.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Mura
authors.affiliation: Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Louis B
authors.initials: LB
authors.lastname: Cantor
authors.affiliation: Department of Ophthalmology and Vision Sciences, University of Toronto Faculty of Medicine, Toronto, Canada. Electronic address: ike.ahmed@utoronto.ca.
authors.forename: Iqbal I K
authors.initials: II
authors.lastname: Ahmed
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D015994:Incidence; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D011183:Postoperative Complications / Q000453:epidemiology*; D011474:Prosthesis Design; D012086:Reoperation; D013997:Time Factors; D014065:Tonometry, Ocular; D014130:Trabeculectomy / Q000379:methods*; D016896:Treatment Outcome; D014792:Visual Acuity