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Oxiradical-dependent photoemission induced by a phacoemulsification probe
S Shimmura1, K Tsubota, Y Oguchi
1Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
Investigative Ophthalmology & Visual Science
|September 1, 1992
Summary
Phacoemulsification devices generate oxygen free radicals during surgery, potentially damaging the cornea. This study visualizes free radical production, confirming its link to ultrasound use and suggesting singlet oxygen involvement.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Surgical Technology
Background:
- Phacoemulsification is a common cataract surgery technique.
- Oxygen free radical formation is a suspected cause of corneal endothelial damage during this procedure.
Purpose of the Study:
- To investigate and visualize free radical production by phacoemulsification probes.
- To determine the role of oxygen free radicals in corneal endothelial damage during surgery.
Main Methods:
- Utilized a single photon-counting camera and an O(2-)-sensitive luciferin derivative (2-methyl-6-[p-methoxyphenyl-3,7-dihydroimidazo [1,2-a]pyrazin-3-one, MCLA) for visualization.
- Measured MCLA-dependent chemiluminescence to detect free radical production.
- Assessed the effect of superoxide dismutase, sodium azide, and deuterium on chemiluminescence.
Main Results:
- Significant increase in MCLA-dependent chemiluminescence within 1 minute of ultrasound activation.
- Chemiluminescence intensity was highest at the probe tip, decreasing distally.
- Chemiluminescence was suppressed by superoxide dismutase and sodium azide.
- Deuterium addition increased chemiluminescence, indicating singlet oxygen involvement.
Conclusions:
- Phacoemulsification probes generate oxygen free radicals, particularly near the probe tip.
- Superoxide and singlet oxygen are implicated in this free radical production.
- Findings support the hypothesis that free radicals contribute to corneal endothelial damage during phacoemulsification.