title: Acoustic cavitation in phacoemulsification and the role of antioxidants.
abstract: Cataract surgery by phacoemulsification generates acoustic cavitation, resulting in formation of reactive oxygen species. The aim of this study was to establish the mechanism of damage by phacoemulsification in an in vitro setting simulating cataract surgery and to assess the protective effects of water-soluble antioxidants. Electron paramagnetic resonance spectroscopy was used to analyze generation of radicals in an intraocular irrigating solution by phacoemulsification instrumentation, operating at an ultrasonic frequency range of 40--60 kHz. Hydroxyl radicals were generated by phacoemulsification under conditions simulating cataract surgery. The effects of water-soluble antioxidants in the irrigating solution on the amounts of radicals were evaluated by electron paramagnetic resonance spectroscopy. The water-soluble antioxidant glutathione, applied in either oxidized or reduced form, decreased hydroxyl radicals concentration measured in the sonicated medium. The effective concentrations of oxidized and reduced glutathione in irrigating solution that significantly eliminate the hydroxyl radical signal were determined in the range of 10(-3)-10(-2) M. Antioxidants should be applied clinically to reduce damage to the corneal endothelium induced by phacoemulsification, thereby improving biosafety.
authors.affiliation: Hillel Yaffe Medical Center, Hadera, Israel. topazmd@netvision.net.il
authors.forename: Moris
authors.initials: M
authors.lastname: Topaz
authors.forename: Vladimir
authors.initials: V
authors.lastname: Shuster
authors.forename: Ehud I
authors.initials: EI
authors.lastname: Assia
authors.forename: Dan
authors.initials: D
authors.lastname: Meyerstein
authors.forename: Naomi
authors.initials: N
authors.lastname: Meyerstein
authors.forename: Dalia
authors.initials: D
authors.lastname: Mazor
authors.forename: Aharon
authors.initials: A
authors.lastname: Gedanken
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004728:Endothelium, Corneal / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D005978:Glutathione / Q000494:pharmacology; D006801:Humans; D018918:Phacoemulsification / Q000009:adverse effects*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012995:Solubility; D013113:Spin Labels; D014465:Ultrasonics
chemical_list: D000975:Antioxidants; D003497:Cyclic N-Oxides; D017382:Reactive Oxygen Species; D013113:Spin Labels; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D005978:Glutathione