Fourier Analysis of Corneal Irregular Astigmatism After Small Incision Lenticule Extraction and Comparison to Femtosecond Laser-Assisted Laser In Situ Keratomileusis

Purpose: Evaluation of spherical component (SC), regular astigmatism (RA), and irregular astigmatism (IA, ie, Asymmetry and Irregularities) 3 years after small incision lenticule extraction (SMILE) and comparison to femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Methods: Thirty-two eyes of 21 patients who underwent SMILE for myopia and astigmatism were compared with 32 eyes of 21 patients treated with FS-LASIK. Scheimpflug images were obtained preoperatively and 3 years postoperatively. Fourier analysis of keratometric-derived parameters (SC, RA, Asymmetry, and Irregularities) of the anterior, posterior, and total cornea were evaluated at 4 concentric rings (ring 1, 2 mm diameter; ring 2, 4 mm; ring 3, 6 mm; ring 4, 8 mm) and over the entire 8-mm zone. Results: After FS-LASIK, over the 8-mm zone, the RA and IA of the anterior cornea increased significantly (P ≤ 0.002), whereas SMILE induced an insignificant increase in RA and Asymmetry (P ≥ 0.276) and a decrease in Irregularities (P = 0.770). At the 8-mm zone of the posterior cornea, the Irregularities increased significantly (P = 0.027) after FS-LASIK, whereas SMILE induced no significant changes in the examined variables (P ≥ 0.347). RA and IA of the total cornea increased significantly after FS-LASIK (P ≤ 0.001), whereas SMILE induced an insignificant increase in RA and Asymmetry (P ≥ 0.092) and a significant decrease in Irregularities (P
Source: Cornea - Category: Opthalmology Tags: Clinical Science Source Type: research