title: Initial Experience With the New Ahmed Glaucoma Valve Model M4: Short-term Results.
abstract: To evaluate the clinical outcomes of the new Ahmed glaucoma valve (AGV) model M4. The device consists of a porous polyethylene shell designed for improved tissue integration and reduced encapsulation of the plate for better intraocular pressure (IOP) control.
  
  
  
  Medical records of patients with an AGV M4 implantation between December 1, 2012 and December 31, 2013 were reviewed. The main outcome measure was surgical failure, defined as either (1) IOP<5 mm Hg or >21 mm Hg and/or <20% reduction of IOP at last follow-up visit, (2) a reoperation for glaucoma, and/or (3) loss of light perception.
  
  
  
  Seventy-five eyes of 73 patients were included. Postoperative IOP at all follow-up visits significantly decreased from a baseline IOP of 31.2 mm Hg (P<0.01). However, IOP increased significantly at 3 months (20.4 mm Hg), 6 months (19.3 mm Hg), and 12 months (20.3 mm Hg) compared with 1 month (13.8 mm Hg) postoperatively (P<0.05). At 6 months and 1 year, the cumulative probability of failure was 32% and 72%, respectively.
  
  
  
  The AGV M4 effectively reduced IOP in the first postoperative month, but IOP steadily increased thereafter. Consequently, failure rates were high after 1 year of follow-up.
authors.affiliation: Glaucoma Research Center, Wills Eye Hospital, Philadelphia, PA.
authors.forename: Victor
authors.initials: V
authors.lastname: Cvintal
authors.forename: Marlene R
authors.initials: MR
authors.lastname: Moster
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Shyu
authors.forename: Katie
authors.initials: K
authors.lastname: McDermott
authors.forename: Feyzahan
authors.initials: F
authors.lastname: Ekici
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pro
authors.forename: Michael
authors.initials: M
authors.lastname: Waisbourd
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000379:methods; D014065:Tonometry, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology