Corneal barrier function, tear film stability, and corneal sensation after photorefractive keratectomy and laser in situ keratomileusis.

PURPOSE

To compare corneal sensation, corneal barrier function, tear secretion, and tear film stability after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

In a prospective study, 28 eyes of 15 patients underwent PRK and 115 eyes of 59 patients underwent LASIK to correct myopia. Corneal sensation, corneal epithelial barrier function, tear secretion, and tear film stability were examined preoperatively and 1 week and 1, 3, 6, and 12 months postsurgery.

RESULTS

Both PRK and LASIK significantly compromised corneal sensation, increased epithelial barrier function, reduced tear secretion, and deteriorated tear film stability (P < .05, Wilcoxon signed-rank test). Deterioration of corneal sensation was significantly greater after LASIK than after PRK by 3 months postoperatively (P < .05, Wilcoxon rank sum test). Increases in corneal epithelial permeability were more prolonged after LASIK than after PRK. A significant intergroup difference in permeability was observed 1 month after surgery (P < .01). Tear breakup time was significantly shorter in the LASIK group than in the PRK group up to 3 months after surgery (P < .045).

CONCLUSIONS

LASIK induces greater and more prolonged damage to corneal sensation, corneal barrier function, and tear film stability than PRK.