[Clinical study of ultrathin flap LASIK and LASEK for the treatment of high myopia with thin cornea].

OBJECTIVE: To explore the efficacy and safety of the ultrathin flap LASIK and LASEK for the treatment of high myopia with central corneal thickness below 500 microm. METHODS: Ultrathin flap LASIK and LASEK were randomly selected to treat high myopic patients with corneal thickness between 450 and 500 microm. 39 cases of 23 patients with average spherical equivalent of -7.51D (range from -6.00 to -9.50D) were treated with ultra thin flap LASIK, and 37 cases of 19 patients with average SE of -7.50D (range from -6.00 to -10.75D) were treated with LASEK. The uncorrected visual acuity, best corrected visual acuity, spherical equivalent, intraocular pressure, haze were examined and recorded 1, 3, 6 and 12 months postoperatively. RESULTS: Postoperative reaction was mild in LASIK patients, who showed a quick recovery in UCVA, whereas LASEK patients needed average 4 days to re-epithelization. At 1, 3, 6, 12 months postoperatively, the percentage of UCVA above 1.0 was 64.1%, 87.2%, 87.2% and 79.3% in LASIK patients and 37.8%, 75.7%, 67.6% and 71.4% in LASEK patients respectively. The percentage of spherical equivalent between +/- 0.50D was 48.7%, 51.3%, 61.5%, 82.8% in LASIK patients and 51.4%, 45.9%, 45.9%, 57.1% in LASEK respectively. There was no severe complications that implicate the BSCVA occurred in-operation and postoperatively. The main complications in LASIK group was corneal flap striae and overcorrection, regression and mild haze in LASEK group. CONCLUSION: Ultrathin flap LASIK had the similar efficacy and safety with LASEK in the treatment of high myopia with thin CCT, but the stability of results and satisfaction from the patients was superior to LASEK.

[Comparison of laser subepithelial keratomileusis and photorefractive keratectomy for the correction of myopia].

OBJECTIVE: To compare the effectiveness and difference between laser subepithelial keratomileusis (LASEK) and conventional photorefractive keratectomy (PRK) for the treatment of myopia up to -8.00 diopter. METHODS: In this prospective study, 46 patients with a manifest refactiion of -1.75 to -8.00 diopters were treated and followed up for 6 months. In each case, PRK was performed in one eye and LASEK in the other eye. The first eye treated and surgical method used in the first eye was randomized. Epithelial healing time, postoperative pain, uncorrected visual acuity (UCVA), manifest refraction, corneal HAZE were followed and compared in PRK and LASEK treated eyes. RESULTS: LASEK eyes took a mean time of 3.49 days to heal the epithelium, whereas PRK eyes took 2.45 days, which is statistically significant (P <0.05). Postoperative pain index was 2.04 and 2.45 in LASEK eyes and PRK eyes respectively (P <0.05). There were no significant differences between eyes in UCVA and manifest refraction during the follow time (P >0.05). However, LASEK-treated eyes showed less corneal haze than PRK eyes. CONCLUSIONS: LASEK can effectively and safely treat myopia up to -8.00 diopters as PRK did, and can diminish early pain after surgery and prevent corneal Haze from happening.