title: Dynamic tube movement of Ahmed glaucoma valve.
abstract: OBJECTIVE
  To report the dynamic movement of the tube of the Ahmed glaucoma valve (AGV) in the anterior chamber with eye movement.
  
  
  METHODS
  Three patients (eyes) with dynamic movement of the tube of the AGV out of approximately 1500 AGV implantations over 10 years were identified. Demographic information, management, and patient outcomes were abstracted from the medical records. Possible mechanisms of the tube movement are discussed.
  
  
  RESULTS
  In all 3 eyes, the fibrovascular capsule and the plate were noted to be stationary in the superior temporal fornix under the conjunctiva and did not move with movement of the eye. The length of the intraocular portion of the tube varied between 3 and 4 mm, depending on the position of the globe. All 3 eyes had undergone at least 1 intraocular procedure before AGV implantation and 2 of 3 eyes had at least 1 intraocular procedure after the AGV implantation. The dynamic movement of the tube was first observed from 0.5 to 7 years after the AGVs were implanted. It was not associated with any intraocular reaction, damage of intraocular tissue, or decrease of intraocular pressure control, and no additional surgical intervention has been required.
  
  
  CONCLUSIONS
  Dynamic movement of the tube of AGV results from dissociation of the fibrovascular capsule and the plate in the fornix from the rotation of the globe. The length of the intraocular portion of the tube may vary widely with eye movement.
authors.affiliation: Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA. law@jsei.ucla.edu
authors.forename: Simon K
authors.initials: SK
authors.lastname: Law
authors.forename: Anne L
authors.initials: AL
authors.lastname: Coleman
authors.forename: Joseph
authors.initials: J
authors.lastname: Caprioli
mesh_terms: D000867:Anterior Chamber; D002648:Child; D004867:Equipment Design; D005133:Eye Movements; D005260:Female; D005548:Foreign-Body Migration / Q000209:etiology* / Q000473:pathology; D020327:Glaucoma Drainage Implants / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies