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Antioxidants reduce corneal light scattering after excimer keratectomy in rabbits
S Jain1, T W Hahn, R L McCally
1Wilmer Institute, Johns Hopkins University, Baltimore, Maryland 21287-9233, USA.
Background And Objective:
Excimer laser-corneal tissue interaction liberates highly reactive free radicals. Our aim was to determine if intraoperative application of antioxidants reduces the postoperative corneal light scattering by minimizing free radical-mediated cellular injury.
Study Design/Materials And Methods:
Phototherapeutic keratectomy (PTK) was performed in 20 rabbit eyes. Following 40-microns epithelial ablation, rabbits were divided into two groups and received 1-minute intraoperative application of either 50% dimethyl sulfoxide and 1% superoxide dismutase or vehicle (balanced salt solution) only. This was followed by a 6-mm diameter 100-microns PTK. Corneal light scattering was measured for 18 weeks using scatterometry. A light scattering index (SI) ranging from 0-10 was calculated; SI = 1 represents normal scattering. Light microscopic examination was performed in selected corneas.
Results:
The mean baseline SI was similar for both groups (P = 0.95). Corneal haze followed a pattern of gradually increasing to peak at 2-3 weeks, and regressing partially thereafter. The decrease in mean SI following antioxidant application (dimethyl sulfoxide and superoxide dismutase) as compared to control group approached significance at 3 weeks (0.1 > P > 0.05) and was highly significant at 9 weeks (P < 0.05).
Conclusion:
Intraoperative application of antioxidants decreases light scattering following excimer keratectomy in rabbit corneas. UV-induced free radicals may play a role in the pathogenesis of corneal light scattering following excimer laser keratectomy.
Insights
Intraoperative antioxidant application significantly reduced corneal light scattering after excimer laser procedures in rabbits. This suggests free radicals contribute to post-keratectomy haze, and antioxidants may mitigate this effect.
Area of Science:
- Ophthalmology
- Laser Surgery
- Corneal Science
Background:
- Excimer laser use in corneal surgery generates reactive free radicals.
- These free radicals may cause cellular injury and lead to postoperative corneal light scattering (haze).
Purpose of the Study:
- To investigate if intraoperative antioxidant application can minimize free radical-mediated cellular injury.
- To determine the effect of antioxidants on reducing postoperative corneal light scattering after excimer keratectomy.
Main Methods:
- Phototherapeutic keratectomy (PTK) was performed on rabbit eyes.
- Eyes received either an antioxidant solution (dimethyl sulfoxide and superoxide dismutase) or a vehicle control intraoperatively.
- Corneal light scattering was measured for 18 weeks using scatterometry.
Main Results:
- Corneal haze peaked at 2-3 weeks post-procedure and partially regressed thereafter.
- Antioxidant treatment showed a trend towards reduced light scattering at 3 weeks (P > 0.05).
- A highly significant reduction in light scattering was observed at 9 weeks in the antioxidant group (P < 0.05).
Conclusions:
- Intraoperative antioxidants effectively decrease light scattering following excimer keratectomy in rabbit corneas.
- UV-induced free radicals are implicated in the pathogenesis of corneal light scattering post-excimer laser keratectomy.