Role of the Corneal Epithelium in Refractive Changes Following Laser in situ Keratomileusis for High Myopia

ABSTRACT PURPOSE: Epithelial hyperplasia is one of the factors that plays a role in myopic regression after photorefractive keratectomy (PRK). We evaluated the role of the epithelium following excimer laser in situ keratomileusis (LASIK) performed on highly myopic eyes. METHODS: Fifty eyes of 32 patients (18 females and 14 males; mean age, 31.7 ± 6.5 years) were treated with LASIK for myopia with an attempted correction ranging between -8.50 and -12.25 D (mean, -10.48 ± 1.43 D). No sutures were placed. The thickness of the central epithelium was evaluated either with a 50-MHz ultrasonic pachymeter or an ultrasound biomicroscope. Postoperatively, topical corticosteroid drops were administered for at least 1 month. RESULTS: Follow-up was at least 12 months. Epithelium measurements were thicker compared to preoperative measurements from the first week postoperatively (mean, +1.9 µm, +2.77%; P<.05). Epithelial thickness peaked at the third month after LASIK (mean, +6.5 /im, +9.5%; P<05) and remained stable through 12 months. A negative correlation between epithelium thickness and manifest refraction from the first month postoperatively to the end of follow-up was present. CONCLUSION: The epithelium seemed to have a role in the regression of refractive effect after LASDX to correct high myopia. [J Refract Surg 2000;16:133-139]