Effect of phacoemulsification fluid flow on the corneal endothelium: experimental study in rabbit eyes.

ABSTRACT

PURPOSE: To quantify the damage to the corneal endothelium from the flow of a balanced salt solution during phacoemulsification. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah. DESIGN: Experimental study. METHODS: 12 New Zealand white rabbits received bilateral surgery. 6 eyes served as controls with no irrigation (incision only). In 18 eyes, the Intrepid Balanced tip of the Centurion Ozil (Alcon Laboratories, Inc.) handpiece was inserted into the anterior chamber for continuous irrigation at 50 mL/min with either 250 or 500 mL of balanced salt solution. After killing humanely and enucleation, the corneas were removed, stained with trypan blue-alizarin red, and photographed in a standardized manner (×400 photographs from 5 specific areas and 1 overview photograph from each corneal button). The ImageJ program was used to evaluate cell damage and loss in the photographs obtained from each cornea. RESULTS: Analysis of the ×400 photographs showed no statistically significant differences between control, 250 mL, and 500 mL groups in the percentage of intact, damaged, or lost cells (P = .896, .851, and .972 respectively). For the overview photographs, the differences in areas of intact and damaged cells among the groups were statistically significant, likely because of the peripheral areas of damage related to touches between the phacoemulsification tip and the endothelium during irrigation. CONCLUSIONS: The volume of balanced salt solution flow alone did not seem to be a major contributing source of endothelial cell damage and loss, providing further insight into mechanisms of corneal endothelium damage during phacoemulsification.