Evaluation of phacoemulsification-induced oxidative stress and damage of cultured human corneal endothelial cells in different solutions using redox fluorometry microscopy

Purpose: To describe the basic concept of redox fluorometry microscopy and investigate its efficacy in evaluating the state of cultured human corneal endothelial cells in different solutions when ultrasonic energy was applied in vitro. Methods: Human corneal endothelial cells from human donor tissue not suitable for transplantation were cultured. A phacoemulsification probe with a 30° round, 1.1- mm TurboSonics® ABS™ Tip (Alcon, Fort Worth, Texas) was introduced into culture dishes filled with balanced salt solution (BSS) and BSS plus (Alcon, Fort Worth, Texas). Cellular autofluorescence images were obtained using a Zeiss inverted microscope. The redox fluorometric ratio, which can be related to cellular metabolism, mitochondrial distribution patterns, which can shift in reaction to environmental changes, and cell size were analysed with a software program. Results: Human corneal endothelial cells exposed to increasing phacoemulsification times and ultrasonic energy displayed dose-dependent decreases in redox ratios. At a lower ultrasonic power and time, BSS plus showed significantly less change in redox ratio than BSS and control (p < 0.05, Mann-Whitney test). As ultrasonic power and time increased, BSS plus had no more significance. Conclusion: Redox fluorometry, with further technological improvement, might be an interesting and potentially useful tool for evaluation of phacoemulsification-induced corneal endothelial damage and screening of protective agents in vitro.