Evaluation of intrastromal corneal ring segments for treatment of post-LASIK ectasia patients with a mechanical implantation technique
Aim: To evaluate the clinical outcomes of Keraring segment implantation in patients with post-laser-assisted in situ keratomileusis (LASIK) ectasia, using a mechanical implantation technique. Materials and Methods: Twelve eyes of 10 patients with post-LASIK ectasia were enrolled. Intracorneal ring segments (ICRS) were implanted aft er dissection of the tunnel using Tunc's specially designed dissector under suction. A complete ophthalmic examination was performed, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent, keratometric (K) readings, inferosuperior asymmetry index (ISAI), and ultrasound pachymetry. All 3, 6, and 12-month follow-ups were completed, and statistical analysis was performed. Results: The mean preoperative UDVA for all eyes was 1.28 +/- 0.59 logMAR. At 12 months, the mean UDVA was 0.36 +/- 0.19 logarithm of the Minimum Angle of Resolution (logMAR) (P=0.002), and the mean preoperative CDVA was 0.58 +/- 0.3 logMAR, which improved to 0.15 +/- 0.12 (P=0.002) at 1 year. There was a significant reduction in cylindrical refractive and spherical equivalent refractive error from -5.29 +/- 2.47 diopters (D) and -5.54 +/- 5.04 D preoperatively to -1.47 +/- 0.71 D and -0.74 +/- 1.07 D (P=0.001, P=0.002), respectively, at 1 year. In the same period, the mean K-readings improved from 47.93 +/- 4.84 D to 40.87 +/- 2.36 D (P=0.002), and the mean ISAI improved from 5.34 +/- 3.05 to 2.37 +/- 1.68 (P=0.003). No significant changes in mean central corneal thickness were observed postoperatively. There were no major complications during or aft er surgery. Conclusion: ICRS implantation using a unique mechanical dissection technique is a safe and effective treatment for post-LASIK ectasia. All parameters showed improvement at 1-year follow-up.