Compensatory Corneal Epithelial Changes After Femtolaser - Assisted Intracorneal Rings Implantation in Early and Moderate Cases of Keratoconus.

Abstract

To study the compensatory corneal epithelial changes after femtolaser-assisted intracorneal ring segment (ICRS) implantation in early and moderate cases of keratoconus (KC) using anterior segment optical coherence tomography (AS-OCT). A prospective observational non-randomized study of 40 eyes with mild to moderate KC received femtolaser-assisted ICRS implantation. Ferrara ICRS with different arc lengths and thicknesses were used according to the patients' tomographic pattern. Patients had a clear central cornea, keratometry reading < 60 diopters, and corneal thickness > 400 microns. AS-OCT was performed preoperatively and at 1, 3, and 6 months after surgery. Corneal epithelial thickness (CET) was measured over 17 points (2 mm central and 16 points on 2-5 mm and 5-7 mm annular zones) over the pupil center. All data were collected and analyzed. Comparing the preoperative and postoperative data, there was a statistically significant increase in the CET postoperatively throughout the 6-month follow-up period in all zones (p<0.001). The epithelial thickness (ET) was noticed shortly around and central to the ring ridges by the first month (5-7 mm zone). By the third month, the flattened central cornea (2 mm zone) and the 2-5 mm zone showed a significant increase in ET up to the 6th month. ICRS implantation in KC results in a thicker and more regular epithelium in the central corneal zone as a secondary response to the corneal stromal changes induced by the implants.