title: Follow-up of the original cohort with the Ahmed glaucoma valve implant.
abstract: OBJECTIVE
  To study the long-term results of the Ahmed glaucoma valve implant in patients with complicated glaucoma in whom short-term results have been reported.
  
  
  METHODS
  In this multicenter study, we analyzed the long-term outcome of a cohort of 60 eyes from 60 patients in whom the Ahmed glaucoma valve was implanted. Failure was characterized by at least one of the following: intraocular pressure greater than 21 mm Hg at both of the last two visits less than 6 mm Hg at both of the last two visits, loss of light perception, additional glaucoma surgery, devastating complications, and removal or replacement of the Ahmed glaucoma valve implant. Devastating complications included chronic hypotony, retinal detachment, malignant glaucoma, endophthalmitis, and phthisis bulbi; we also report results that add corneal complications (corneal decompensation or edema, corneal graft failure) as defining a devastating complication.
  
  
  RESULTS
  The mean follow-up time for the 60 eyes was 30.5 months (range, 2.1 to 63.5). When corneal complications were included in the definition of failure, 26 eyes (43%) were considered failures. Cumulative probabilities of success at 1, 2, 3, and 4 years were 76%, 68%, 54%, and 45%, respectively. When corneal complications were excluded from the definition of failure, 13 eyes (21.5%) were considered failures. Cumulative probabilities of success at 1, 2, 3, and 4 years were 87%, 82%, 76%, and 76%, respectively. Most of the failures after 12 months of postoperative follow-up were because of corneal complications.
  
  
  CONCLUSIONS
  The long-term performance of the Ahmed glaucoma valve implant is comparable to other drainage devices. More than 12 months after the implantation of the Ahmed glaucoma valve implant, the most frequent adverse outcome was corneal decompensation or corneal graft failure. These corneal problems may be secondary to the type of eyes that have drainage devices or to the drainage device itself. Further investigation is needed to identify the reasons that corneal problems follow drainage device implantation.
authors.affiliation: Jules Stein Eye Institute, University of California, Los Angeles, School of Medicine, 90095-7004, USA.
authors.forename: F
authors.initials: F
authors.lastname: Topouzis
authors.forename: A L
authors.initials: AL
authors.lastname: Coleman
authors.forename: N
authors.initials: N
authors.lastname: Choplin
authors.forename: M M
authors.initials: MM
authors.lastname: Bethlem
authors.forename: R
authors.initials: R
authors.lastname: Hill
authors.forename: F
authors.initials: F
authors.lastname: Yu
authors.forename: W C
authors.initials: WC
authors.lastname: Panek
authors.forename: M R
authors.initials: MR
authors.lastname: Wilson
mesh_terms: D005260:Female; D018463:Filtering Surgery / Q000379:methods*; D005500:Follow-Up Studies; D005901:Glaucoma / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011183:Postoperative Complications; D011475:Prosthesis Failure; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity