Acoustic cavitation in phacoemulsification and the role of antioxidants

Protective effect of free-radical scavengers on corneal endothelial damage in phacoemulsification

“…BSS Plus thus provides only partial protection from corneal damage by the antioxidative properties of GSSG and dextrose. As demonstrated in an in vitro study 49 and confirmed in the present in vivo study, the concentration of 10 À4 M GSSG, as in BSS Plus, is too low to eliminate the adverse effects of hydroxyl radicals. As anticipated from our previous in vitro data, the GSSG 10 À3 M group, with a mean cellular loss of 5.2%, provides better protection than the BSS Plus solution, indicating a direct correlation of endothelial cell protection with the concentration of antioxidants in the irrigating solution.…”

“…48 Studies using corneal tissue test chambers found that corneal endothelium appeared healthier, with a higher density, if the irrigating solution contained glutathione, 43,46,47 and other studies support the protective effect of glutathione on corneal endothelial cells. 21,42 In in vitro studies, 49 we recently determined that the effective concentrations of oxidized and reduced glutathione required to eliminate the hydroxyl radical signal are on the order of 10 À2 M.…”

“…It seems, however, that the effective concentration of GSSG in the irrigating solution should be in the range of 10 À2 M to significantly eliminate the hydroxyl radical effects in clinical use. 49 In practice, it is hard to dissolve this high concentration of GSSG in the BSS irrigating solution; the solution is chemically unstable and rather expensive.…”

Role of cavitation in the phacoemulsification process

“…16 It has also been shown that the generation of free radicals during phacoemulsification can cause adverse effects on the cellular and subcellular levels through diverse mechanisms, one of which is acoustic cavitation. 5,17 At certain US levels, therapeutic high-intensity energy phacoemulsification may create cavitation. Cavitation is the phenomenon of rapid formation and subsequent collapse of bubbles from the vaporization of liquid in regions of low pressure.…”

Effect on corneal endothelial cell loss during phacoemulsification: Fortified balanced salt solution versus Ringer lactate

“…13 Few human studies have compared Ringer lactate and BSS Plus, and most were in the context of extracapsular cataract extraction (ECCE) or vitrectomy, both of which are of long duration compared with phacoemulsification. 14,15 The mechanism of corneal endothelial damage in phacoemulsification is free-radical mediated and is the result of the highintensity ultrasound energy used 5,16 ; this is different from the mechanism in ECCE. Most studies were of animals; however, human and animal corneas behave differently to tissue injury, healing, and regeneration.…”