title: Clinical outcomes after Ahmed valve implantation in refractory paediatric glaucoma.
abstract: OBJECTIVE
  To evaluate clinical outcomes after Ahmed valve implantation in refractory paediatric glaucoma.
  
  
  METHODS
  A retrospective review was conducted on 34 eyes from 29 patients with refractory glaucoma, who were younger than 18 years of age and who underwent Ahmed valve implantation. The main outcome measures were intraocular pressures (IOPs) and the number of glaucoma medications used. Qualified success was defined as IOP <or=21 mm Hg regardless of the number of glaucoma medications. Complete success was defined as IOP <or=21 mm Hg without glaucoma medication.
  
  
  RESULTS
  Mean age at operation was 5.5 years (range, 0-16). Fifteen eyes (44.1%) had undergone previous glaucoma surgery before Ahmed valve implantation. Mean follow-up time was 29.1 months (range, 3-31). IOP was reduced from a preoperative mean of 37.5+/-7.3 to 18.4+/-7.3 mm Hg at 6 months postoperatively (P<0.01). At 12 months after surgery, the success rates were 63.3% (qualified success) and 13.3% (complete success). The cumulative probabilities of qualified success at 6, 12, and 24 months after Ahmed valve implantation were 89.0, 68.6, and 45.7%, respectively. The median time of survival was 19.6+/-0.9 months.
  
  
  CONCLUSIONS
  Ahmed valve implantation is effective in lowering IOP in refractory paediatric glaucoma, with limited survival after long-term follow-up. Addition of a second Ahmed valve may be effective in the management of failure after primary implantation.
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: H K
authors.initials: HK
authors.lastname: Yang
authors.forename: K H
authors.initials: KH
authors.lastname: Park