title: Surgical Outcomes of Additional Ahmed Glaucoma Valve Implantation in Refractory Glaucoma.
abstract: To evaluate the surgical outcomes of the implantation of an additional Ahmed glaucoma valve (AGV) into the eyes of patients with refractory glaucoma following previous AGV implantation.
  
  
  
  This study is a retrospective review of the clinical histories of 23 patients who had undergone a second AGV implantation after a failed initial implantation. Age, sex, prior surgery, glaucoma type, number of medications, intraocular pressure (IOP), visual acuity, and surgical complications were analyzed. Surgical success was defined as IOP maintained below 21 mm Hg, with at least a 20% overall reduction in IOP, regardless of the use of IOP-lowering medications.
  
  
  
  Following the implantation of a second AGV, the mean IOP decreased from 39.3 to 18.5 mm Hg (52.9% reduction, P<0.001). The mean number of postoperative IOP-lowering medications administered decreased from 2.8 to 1.7 after the second AGV implantation (P<0.001). The cumulative probability of success for the procedure was 87% after 1 year and 52% after 3 years. Three patients (13.0%) experienced bullous keratopathy after the second AGV implantation. None of the patients showed any evidence of diplopia or ocular movement limitation as a result of the presence of 2 AGVs in the same eye. Prior trabeculectomy was found to be a significant risk factor for failure (P=0.027).
  
  
  
  A second AGV implantation can be a good choice of surgical treatment when the first AGV has failed to control IOP.
authors.affiliation: Department of Ophthalmology, Kim's Eye Hospital, Myung-Gok Eye Research Institute, Konyang University, Seoul, Korea.
authors.forename: Sung Ju
authors.initials: SJ
authors.lastname: Ko
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Hwang
authors.forename: Sang Il
authors.initials: SI
authors.lastname: Ahn
authors.forename: Hwang Ki
authors.initials: HK
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005901:Glaucoma / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012189:Retrospective Studies; D012307:Risk Factors; D014065:Tonometry, Ocular; D014130:Trabeculectomy / Q000379:methods*; D016896:Treatment Outcome; D014792:Visual Acuity; D055815:Young Adult