title: Use of microbubble ultrasound contrast agent to demonstrate the iris valve effect in human eye bank eyes.
abstract: OBJECTIVE
  To demonstrate that the interface between the normal iris and the lens surface functions as a flap valve.
  
  
  METHODS
  Microbubble ultrasound contrast agent was injected into the anterior and posterior chambers of human eye bank eyes and the distribution of contrast imaged with high-frequency ultrasound.
  
  
  RESULTS
  Contrast agent did not enter the posterior chamber when injected into the anterior chamber, but contrast agent injected into the posterior chamber easily flowed into the anterior chamber.
  
  
  CONCLUSIONS
  The iris-lens interface normally functions as a flap valve, preventing retrograde flow from the anterior to the posterior chamber. A temporary increase in anterior chamber pressure thus results in iris concavity in pigmentary dispersion syndrome.
authors.affiliation: Department of Ophthalmology, Ontario Cancer Institute, Princess Margaret Hospital, University of Toronto, Canada. cpavlin@home.com
authors.forename: C J
authors.initials: CJ
authors.lastname: Pavlin
authors.forename: P N
authors.initials: PN
authors.lastname: Burns
authors.forename: F S
authors.initials: FS
authors.lastname: Foster
mesh_terms: D000328:Adult; D000867:Anterior Chamber / Q000000981:diagnostic imaging*; D001082:Aqueous Humor / Q000378:metabolism; D003287:Contrast Media / Q000378:metabolism*; D005125:Eye Banks; D006801:Humans; D007498:Iris / Q000000981:diagnostic imaging / Q000502:physiology*; D007908:Lens, Crystalline / Q000000981:diagnostic imaging / Q000502:physiology*; D009799:Ocular Physiological Phenomena; D011108:Polymers; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D011108:Polymers; C105825:SH U 563 A