Relationship between postoperative intraocular pressure elevation and residual sodium hyaluronate following phacoemulsification and aspiration

Abstract

Purpose: 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).Setting: 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).Conclusion: The sod ium-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.