A Comparison of Porcine Lens Storage Methods for Optimal Phacoemulsification

Objective: The study purpose was to compare effects of two porcine lens storage methods on phacoemulsification efficiency and chatter. Methods: This in vitro laboratory study was conducted at the John A. Moran Eye Center Laboratories, University of Utah. Porcine nuclei were fixed in 10% formaldehyde and cut into 2.0 mm cubes. An equal number of lens cubes either were stored in a 100% humidity chamber or were partially immersed in balanced salt solution (BSS). Using identical parameters on the phacoemulsification machine, 40 lenses that underwent each storage method were phacoemulsified every two hours for a total of ten hours. Results: Lenses stored in the 100% humidity chamber experienced a 2.25% increase in efficiency per hour (r2=0.1922; p=0.3846), while lenses stored partially immersed in BSS experienced a 1.30% increase in efficiency per hour (r2=0.4084; p=0.1719). Although we found no statistically significant difference between the two groups, the partially immersed lenses were consistently softer than the lenses that were kept in the 100% humidity chamber. Chatter was minimal throughout the testing, but showed an increase over time. Conclusion: Either the 100% humidity chamber or the partially submerged method can be used for lens storage. Despite some differences between the two storage methodologies, the differences were not statistically significant. We conclude that using either method results in a natural softening of the lenses over time which must be taken into consideration during future experiments. This necessitates the testing time to be as short as possible.