Viscoelastic adherence to corneal endothelium following phacoemulsification

Purpose: To compare the residual adherence of viscoelastics to the corneal endothelium following phacoemulsification in an in vitro rabbit model. Setting: Departments of Ophthalmology and Anatomy, Wayne State University, Detroit, Michigan, USA. Methods: Three groups of 10 rabbit eyes each had a lensectomy via phacoemulsification using sodium hyaluronate (Amvisc Plus(R), Healon GV(R)) or sodium chondroitin sulfate-sodium hyaluronate (Visoat(R)) as the viscoelastic agent. Alter phacoemulsification and cortex removal, a central corneal block was excised, cryofixed, and processed for light and electron microscopy. Viscoelastic thickness was determined by a calibrated reticule on the light microscope or a calibrated measuring program in the electron microscope. The nonparametric statistical test, Kruskal-Wallis, was used to compare viscoelastic groups. Results: Median phacoemulsification time between viscoelastic agents was not significantly different. Median viscoelastic thicknesses were 13.0 mu m for Amvisc Plus, 0.4 mu m for Healon GV, and 375.0 mu m for Viscoat, Each was significantly different from the others (Kruskal-Wallis, P < .001). Conclusions: Median thickness of Amvisc Plus, Healon GV, and Viscoat remaining adherent to the corneal endothelium after phacoemulsification as markedly different. Viscoat provided the greatest amount of viscoelastic material adjacent to the corneal endothelium.