Comparison of corneal nerve regeneration and sensitivity between LASIK and laser epithelial keratomileusis (LASEK)

PURPOSE: To compare changes in corneal nerve fibers and keratocyte density by confocal microscopy after laser-assisted in situ keratomileusis (LASIK) and laser epithelial keratomilcusis (LASEK). DESIGN: Prospective, nonrandomized comparative clinical trial. METHODS: Fifty,six eyes of 28 patients who underwent LASIK and 52 eyes of 26 patients who underwent LASEK were included. Confocal microscopic data of the central cornea, corneal sensitivity, tear film breakup time, and Schirmer values were determined at three and six months after LASIK or LASEK treatment. RESULTS: In the LASIK group, corneal sensitivity was reduced from preoperative levels at six months after surgery. In the LASEK group, however, there was no difference between baseline and six-month postoperative values. The number of subbasal nerve fibers and the keratocyte density were also different in the LASIK an LASEK groups. The regeneration of corneal nerves correlated strongly with the recovery of corneal sensation and keratocyte density in both groups, whereas the tear film breakup time, Schirmer values, and epithelial thickness did not correlate with corneal nerve regeneration in either group. CONCLUSIONS: The greater decrease in the number of subbasal nerve fibers in the LASIK group compared with the LASEK group may relate to the greater decrease in corneal sensitivity. The pattern of corneal nerve re generation and the recovery of corneal sensation after LASEK did not differ greatly from that after photorefractive keratectomy in previous studies.