Effects of hydrogen in prevention of corneal endothelial damage during phacoemulsification: a prospective randomized clinical trial

Purpose Hydrogen (H2) has been reported to scavenge free radicals, particularly the hydroxyl radical (·OH). Ultrasound oscillation in an aqueous solution produces ·OH. Our recent study demonstrated that H2 dissolved in an irrigation solution prevented corneal endothelial damage during phacoemulsification in an animal model. We examined the effects of H2 during clinical phacoemulsification. Design A single-center, prospective, randomized, double-masked clinical trial. Methods Thirty-two patients who had cataracts of similar nucleus hardness in both eyes (age: 75.4±7.68 years; 17 males, 15 females) were recruited. Phacoemulsification was performed using a solution of dissolved H2 in one eye, and a conventional solution in the contralateral eye. Endothelial cell density (ECD) at the center of the cornea was measured using noncontact specular microscopy preoperatively and at 1 day, 1 week, and 3 weeks postoperatively. Results Reduction rates of ECD (mean ± standard deviation) were 16.0%±15.7% at 1 day, 15.4%±16.1% at 1 week, and 18.4%±14.9% at 3 weeks in the control group, compared to 6.5%±8.7% at 1 day (P = .003), 9.3%±11.0% at 1 week (P = .039), and 8.5%±10.5% at 3 weeks (P = .004) in the H2 groups. These rates were significantly smaller in the H2 group at all time points. Conclusions H2 dissolved in irrigation solution reduced corneal endothelial damage during phacoemulsification. This suggests that a considerable part of the corneal endothelial damage during phacoemulsification is caused by oxidative stress, and that H2 is useful in clinical phacoemulsification.