title: Influence of elevated intraocular pressure on the posterior chamber-anterior hyaloid membrane barrier during cataract operations.
abstract: OBJECTIVE
  To investigate the influence of elevated intraocular pressure on the posterior chamber-anterior hyaloid membrane (PC-AHM) barrier during cataract operations in ex vivo porcine eyes.
  
  
  METHODS
  A pressure transducer was connected to porcine eye anterior chambers (ACs). In experiment 1, ACs were perfused for 20 seconds with balanced salt solution containing 1.0-μm fluorescein beads (10 eyes per bottle height: 45, 85, 145, and 285 cm). In experiment 2, 5 ophthalmic viscosurgical devices with different molecular weights and sodium hyaluronate concentrations were infused into the ACs (20 eyes per ophthalmic viscosurgical device). After continuous curvilinear capsulorrhexis, hydrodissection was performed. After both experiments, PC-AHM barrier staining was evaluated through the Miyake-Apple view.
  
  
  RESULTS
  Types of fluorescein staining patterns were classified as AC, zonule of Zinn, AHM, AHM tear, and ruptured capsule. In experiment 1, plateau intraocular pressure and staining type were positively correlated (Spearman rank correlation; r = 0.703, P < .001). In experiment 2, mean peak intraocular pressure was significantly greater in the ruptured capsule-type eyes than in the AC-, zonule of Zinn-, AHM (P < .001), or AHM-tear-(P = .02) type eyes, as well as in the AHM- and AHM-tear-type eyes compared with the AC and zonule of Zinn type eyes (P < .001). Intraocular pressure was significantly higher in eyes infused with ophthalmic viscosurgical devices with a higher molecular weight or sodium hyaluronate concentration (P < .05).
  
  
  CONCLUSIONS
  Stress on the PC-AHM barrier increases as intraocular pressure increases. Ophthalmic viscosurgical devices with a higher molecular weight or sodium hyaluronate concentration might induce increased IOP during cataract operations.
  
  
  CONCLUSIONS
  To maintain normal PC-AHM barrier function, excessive intraocular pressure should be avoided during cataract operations.
authors.affiliation: Departments of Ophthalmology, Ehime University Graduate School of Medicine, Shitsukawa, Toon-City, Ehime, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Kawasaki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Tasaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zheng
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shiraishi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Uno
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ohashi
mesh_terms: D000818:Animals; D018916:Blood-Aqueous Barrier; D002386:Cataract / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D002387:Cataract Extraction; D004195:Disease Models, Animal; D007429:Intraocular Pressure / Q000502:physiology*; D007432:Intraoperative Period; D008566:Membranes / Q000378:metabolism / Q000473:pathology*; D057972:Posterior Eye Segment / Q000378:metabolism / Q000473:pathology*; D013552:Swine