title: Outcomes of Ahmed valve surgery for refractory glaucoma in Dhahran, Saudi Arabia.
abstract: OBJECTIVE
  To evaluate the outcomes of Ahmed glaucoma valve (AGV) implantation surgery for refractory glaucoma.
  
  
  METHODS
  This one-armed historical cohort study was conducted in 2011. Refractory glaucoma was defined as eyes with an intraocular pressure (IOP) greater than 21 mm Hg with maximally tolerated glaucoma medications, failed surgeries, or both. For all eyes with refractory glaucoma that underwent AGV implantation, data were collected on IOP, the best corrected visual acuity (BCVA) and glaucoma medications preoperatively and 4, 6, 12, 24 and 56wk postoperatively. Logarithm values of IOP were calculated and compared.
  
  
  RESULTS
  The study group was comprised of 30 patients (30 eyes, 16 males and 14 females) with refractory glaucoma. Mean preoperative IOP was 39.3±13.8 mm Hg. Postoperative mean IOP was 15.7±7.1 mm Hg, 19.6±12.8 mm Hg and 13.9±14.2 mm Hg at 12, 24 and 56wk respectively. BCVA was ≥ 6/60 in 11 eyes preoperatively, and five eyes had BCVA≥6/60 at 56wk postoperatively. Preoperatively, more than four medications were used to treat glaucoma in 21 eyes. At 12wk postoperatively, no medications were required to control IOP in 20 eyes. At 56wk postoperatively, at least one medication was required to control IOP in 10 eyes. Over the entire follow up period, four eyes were treated with yttrium aluminium garnet (YAG) laser and 14 eyes required a second surgery. The AGV was removed in four eyes.
  
  
  CONCLUSIONS
  AGV implantation reduced IOP and the number of medications required to control refractory glaucoma. However, there was a higher risk of decreased vision. Long-term follow up and prompt intervention are recommended.
authors.affiliation: Department of Ophthalmology, Imam Mohammed Bin Saud University, Riyadh 11432, Saudi Arabia.
authors.forename: Tariq
authors.initials: T
authors.lastname: Alasbali
authors.affiliation: Department of Ophthalmology, King Fahad hospital, Albaha 21491, Saudi Arabia.
authors.forename: Abdullah Ali
authors.initials: AA
authors.lastname: Alghamdi
authors.affiliation: Department of Research, King Khaled Eye Specialist Hospital, Riyadh 11462, Saudi Arabia.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Khandekar
keywords: Ahmed glaucoma valve surgery; blindness; refractory glaucoma