[Recovery of corneal sensitivity in extremely high myopia after laser sub-epithelium keratomileusis]

To evaluate the changes in corneal sensitivity following laser epithelial keratomileusis (LASEK) and epiploic laser in situ keratomileusis (Epi-LASIK) in treatment of extremely high myopia.

Thirty-seven eyes of 37 patients underwent LASEK and Epi-LASIK to correct myopia, their equivalent sphere ranged from -9.50 DS to -12.50 DS, astigmatism < +/- 1.50 DC. Cornea sensitivity was measured with a Cochet-Bonnet esthesiometer at central part of the cornea. Treated eyes were divided into two groups by different operation methods: Epi-LASIK group and LASEK group. After the operation, each group was divided into two sub-groups according to the eyes with or without obvious epithelium edema.

Obvious epithelium sheet edema happened in 6 eyes after LASEK and 3 eyes among them were due to broken epithelium sheets during the operation. By 2 weeks, 1, 2, 3 and 6 months after Epi-LASIK, corneal sensitivity recovered to 79.31%, 84.49%, 87.92%, 92.24% and 93.98% of preoperative level, respectively. Compare to the Epi-LASIK, cornea sensitivity after LASEK recovered to 69.64%, 78.57%, 83.21%, 85.70% and 87.86% of preoperative level, respectively. The recovery of corneal sensation in LASEK group was slower than that of Epi-LASIK group. The difference between these two groups was statistically significant at 2 weeks after the operation (P < 0.05). In LASEK group, there was a trend towards a great reduction in corneal sensitivity in epithelium edema eyes and the recovery was slower in these eyes. The difference of corneal sensitivity recovery between these two sub-groups was statistically significant (P < 0.05).

The recovery of corneal sensitivity in extremely high myopia after Epi-LASIK is faster than that after LASEK, and reached to the platform stage by 3 months. The epithelium sheet edema after LASEK affects corneal sensitivity recovery.