Comparison Between Epithelial Mapping Changes After Photorefractive Keratectomy And Femto-Smile For Myopic Astigmatism

The aim of the study is to compare changes in epithelial mapping changes before and after photorefractive keratectomy (PRK) and Femtosecond laser-assisted Small Incision Lenticule Extraction (Femto-SMILE) for the correction of myopia and myopic astigmatism.

The study was carried out in Roayah vision correction center, Alexandria, Egypt

The study was a prospective interventional comparative study that included 48 eyes of 2 patients. The eyes were dividrd into two groups; Group A include 24 eyes who treated with photorefractive keratectomy, while group B include the same number of eyes and treated by Femto-SMILE. Before surgery, all patients were subjected to  full ophthalmologic examination and corneal imaging. All patients were examined at one week, one month, and three months postoperatively. The follow-up examination included: slit lamp examination, uncorrected and best corrected visual acuity. Corneal topography and epithelial mapping was performed to all cases using MS-39 before surgery and at one week, one month and three months after surgery.

In our study, the mean preoperative minimum epithelial thickness in group A was 42.33 μm and that in Group B was 44.25 μm. The mean preoperative maximum epithelial thickness in Group A was 54.46 μm and that in Group B was 54.25 μm. After three months of surgery, we noticed an increase in the thinnest epithelial point in all patients. There were no statistically significant changes in epithelial thickness in the four paracentral quadrants between the groups. The central 3 mm of the corneal epithelium was significantly thicker after PRK at the first postoperative visit.

PRK and Femto-SMILE show very high accuracy and predictability in the correction of myopia and myopic astigmatism. There was no significant difference in epithelial thickness between patients treated with PRK and those treated with Femto-SMILE.