The short-term effect of excimer lasers for PRK and LASIK on corneal endothelial cell density loss.

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Worranart Tattiyakul


Purpose: To study the effects of excimer lasers for PRK and LASIK procedures on cornea endothelial cell density loss compared to a control group at 30 days post-operatively.
Methods: A prospective cohort comparative study, comprised of 240 eyes from 120 patients. An excimer laser treated group who underwent PRK or LASIK procedures by Alcon Wavelight EX500 (mean age 27.83 ±8.63 years) was compared to a control group without ocular comorbidities who never had ocular procedures (mean age 32.67 ±7.88 years). Both groups were followed-up for corneal endothelial cell density (ECD) using non-contact specular microscopy on day 0 and 30 of the study period. All patients gave written informed consent and all procedures in this study were performed by one surgeon. Analysis; dependent t-test for day 0 vs 30 ECD loss and multivariable linear regression models were used to adjust for baseline differences between the two groups.
Results: For all 120 eyes in the excimer laser treated group, ECD loss at 30 days post-procedure is significantly higher than the control group (excimer laser treated group vs control group respectively; -92.44 ±187.49 cells/mm2, -7.48 ±233.61 cells/mm2, p-value <0.001). Multivariable regression model predicts ECD loss at 30 days of -60.31 cells/mm2 (95% CI: -115.53 – 5.09, p value 0.032) or 2.41% of baseline ECD compared to control group. Each incremental 1% increase in baseline pleomorphism of endothelial cells can significantly increase the ECD loss at 30 days post-procedure by -10.06 cells/mm2 (95% CI-14.34 –-5.78). One standard deviation increase in pleomorphism can cause an additional 3.19% of ECD loss at 30 days.
Conclusion: ECD loss at 30 days post-excimer laser procedures is significantly higher than the control group. An elevated baseline of corneal endothelium pleomorphism can exacerbate ECD loss at 30 days post excimer laser. Caution is advised regarding corneal endothelial health when selecting candidates for excimer laser treatment.
Conflicts of interest: None.


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