title: Relationship between postoperative intraocular pressure elevation and residual sodium hyaluronate following phacoemulsification and aspiration.
abstract: OBJECTIVE
  To investigate the relationship between postoperative intraocular pressure (IOP) elevation and the amount and viscosity of sodium hyaluronate remaining in the anterior chamber after phacoemulsification and aspiration (PEA).
  
  
  METHODS
  Hachioji Medical Center and Tokyo Medical College Hospital, Tokyo, Japan.
  
  
  METHODS
  In 107 eyes, washout (irrigation and aspiration [I/A]) of sodium hyaluronate was performed for randomly assigned durations of 5, 10, or 20 seconds following PEA and intraocular lens (IOL) implantation. At the conclusion of washout, the flow from the I/A tip was reversed and a sample of the irrigating solution obtained from the anterior chamber. The residual sodium hyaluronate concentration was measured by sandwich assay. The kinematic viscosity of the sample was calculated from a regression equation derived from measured viscosities of standard hyaluronate solutions of various concentrations.
  
  
  RESULTS
  The preoperative mean IOP in the groups that received 5-, 10-, and 20-second washout was 11.9, 10.9, and 11.6 mm Hg, respectively. The mean IOP on the first postoperative day in the 5-second group was significantly higher (P = .001, Kruskal-Wallis test) than those in the 10- and 20-second groups (10.8 and 11.6 mm Hg, respectively). A significant correlation was observed between residual hyaluronate concentration and IOP on the first postoperative day (Spearman's rank correlation coefficient 0.319, n = 80, P = .045) and also between kinematic viscosity and IOP on the first postoperative day (one-factor analysis of variance, P < .001).
  
  
  CONCLUSIONS
  The sodium-hyaluronate-induced IOP elevation is related to its viscosity as well as to its high molecular weight. Washout times of at least 10 seconds are desirable to prevent IOP elevation.
authors.affiliation: Department of Ophthalmology, Tokyo Medical College Hospital, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Inoue
authors.forename: S
authors.initials: S
authors.lastname: Kudo
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000187:drug effects; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000009:adverse effects* / Q000032:analysis; D007429:Intraocular Pressure; D007700:Kinetics; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009798:Ocular Hypertension / Q000139:chemically induced* / Q000503:physiopathology; D018918:Phacoemulsification / Q000379:methods*; D011184:Postoperative Period; D013396:Suction; D007507:Therapeutic Irrigation; D014783:Viscosity
chemical_list: D006820:Hyaluronic Acid