Effects of Hydrogen in Prevention of Corneal Endothelial Damage During Phacoemulsification: A Prospective Randomized Clinical Trial

Purpose Hydrogen (H 2 ) 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 H 2 dissolved in an irrigation solution prevented corneal endothelial damage during phacoemulsification in an animal model. We examined the effects of H 2 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 H 2 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 H 2 groups. These rates were significantly smaller in the H 2 group at all time points. Conclusions H 2 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 H 2 is useful in clinical phacoemulsification.