title: Comparison of polypropylene and silicone Ahmed valve survival 2 years following implantation in the first 2 years of life.
abstract: OBJECTIVE
  To compare the 2-year survival rates of polypropylene and silicone Ahmed glaucoma valves (AGVs) implanted during the first 2 years of life.
  
  
  METHODS
  Retrospective analysis of polypropylene and silicone AGV implantation during the first 2 years of life in children with 2 years' postoperative follow-up. Patients with prior aqueous drainage device implantation were excluded.
  
  
  RESULTS
  Forty-two eyes of 36 children were reviewed. Thirty-one eyes received a polypropylene AGV (six S1, 25 S2), and 11 eyes received a silicone AGV (11 FP7). The average survival time (maintenance of intraocular pressure < or =22 mm Hg with (or without) medications and without significant complications) was significantly longer (p = 0.001 by the logrank test) for the silicone group (23.36 months, standard error (SE) 1.64, 95% confidence interval (CI) 20.16 to 24.00 months) than for the polypropylene group (19.10 months, SE 1.53, 95% CI 16.1 to 22.12 months). Cumulative probabilities of survival at 2 years by Kaplan to Meier analysis were 90.9% (SE 8.7, 95% CI 70 to 100%) and 54.8% (SE 8.9, 95% CI 23 to 87%), respectively (p = 0.001 by the logrank test). All eyes implanted with silicone AGVs had the diagnosis of congenital glaucoma, which was independently associated with 2-year survival.
  
  
  CONCLUSIONS
  Two years after surgery, silicone AGVs survived longer than polypropylene AGVs. However, all eyes that received silicone AGVs in our cohort had congenital glaucoma, which had a better survival than other paediatric glaucoma diagnoses. A study of silicone AGV implantation in other paediatric glaucoma diagnoses is needed to determine whether or not silicone AGVs independently have a better survival after implantation in the first 2 years of life.
authors.affiliation: Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, PO Box 7191, Riyadh 11462 Saudi Arabia. arif.khan@mssm.edu
authors.forename: A O
authors.initials: AO
authors.lastname: Khan
authors.forename: F
authors.initials: F
authors.lastname: Al-Mobarak
authors.forename: F A
authors.initials: FA
authors.lastname: Almobarak
mesh_terms: D019544:Equipment Failure Analysis; D005260:Female; D005901:Glaucoma / Q000151:congenital / Q000503:physiopathology / Q000601:surgery*; D020327:Glaucoma Drainage Implants; D006801:Humans; D007223:Infant; D007429:Intraocular Pressure; D008297:Male; D011126:Polypropylenes; D011474:Prosthesis Design; D012086:Reoperation; D012189:Retrospective Studies; D012826:Silicone Elastomers; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D011126:Polypropylenes; D012826:Silicone Elastomers