title: Primary valve malfunction of the Krupin eye valve with disk.
abstract: OBJECTIVE
  To examine the management and possible causes of primary valve malfunction of the Krupin eye valve with disk.
  
  
  METHODS
  The authors reviewed the results of 113 patients undergoing implantation of the Krupin eye valve with disk and identified eight patients with primary valve malfunction requiring surgical revision.
  
  
  RESULTS
  Valve revision involved manipulation (n = 1 case), explantation of the malfunctioning valve and implantation of a new valve (n = 2), and amputation of the valve (n = 5). Six of eight patients had final intraocular pressures of < 21 mmHg on one or no medications at a mean interval of 15.9 months (range 5-36) after surgical revision. Transient postoperative hypotony was noted in three patients and chronic hypotony with loss of light perception in one patient. One explanted valve was examined and found to have partially fused leaflets.
  
  
  CONCLUSIONS
  Surgical revision in cases of primary valve malfunction of the Krupin eye valve with disk may be accomplished relatively safely with an acceptable level of postoperative complications. The etiology of primary valve malfunction may be related to the sterilization process and prolonged storage before implantation.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Burchfield
authors.forename: M A
authors.initials: MA
authors.lastname: Kass
authors.forename: M B
authors.initials: MB
authors.lastname: Wax
mesh_terms: D018463:Filtering Surgery; D005500:Follow-Up Studies; D005901:Glaucoma / Q000601:surgery; D006801:Humans; D007429:Intraocular Pressure; D015814:Ocular Hypotension / Q000209:etiology / Q000601:surgery; D011183:Postoperative Complications / Q000209:etiology / Q000601:surgery; D019736:Prostheses and Implants / Q000009:adverse effects*; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies