Incidence of corneal epithelial defects with the standard and zero-compression hansatome microkeratomes

To evaluate the incidence of epithelial defects in patients who have had laser in situ keratomileusis (LASIK) surgery with the standard compression Hansatome microkeratome head in comparison to the modified (zero-compression) Hansatome microkeratome head (Bausch & Lomb, Rochester, NY).

This study was a retrospective review of 404 consecutive patients who had LASIK surgery on both eyes between January 2002 and June 2002. The standard compression microkeratome head was used in 216 (53%) cases and the zero-compression microkeratome head was used in 188 (47%) cases. Epithelial defects were categorized as loose epithelium, or a break in the epithelium, within the area of the flap. An adverse outcome for a patient was defined as having an epithelial defect in at least one eye. Odds ratios were estimated using logistic regression.

When the standard compression microkeratome head was used, 19 (8.8%) patients had an epithelial defect in at least 1 eye. When the zero-compression microkeratome head was used, 5 (2.7%) patients had an epithelial defect in at least 1 eye. Logistic regression comparing the risk of epithelial defect in either eye with the standard compression head versus the zero-compression head resulted in an age-adjusted odds ratio of 0.2 (95% confidence interval, 0.07 to 0.58, P < .05).

These findings provide evidence that LASIK surgery with a zero-compression head reduces the risk of epithelial defect compared to the standard compression head of the Hansatome microkeratome.