Efficacy of intrastromal corneal ring segments in the treatment of keratoconus with irregular asymmetric paracentral astigmatism

Abstract

Purpose. To evaluate the efficacy and safety of implantation of intrastromal corneal ring segments ICRS (IRS NEP MNTC) in patients with keratoconus with irregular asymmetric paracentral astigmatism. Material and methods. 14 patients (16 eyes) with keratoconus stage II–III with irregular asymmetric paracentral astigmatism were evaluated before and after ICRS (IRS NEP MNTC). The tunnels for ICRS implantation were created with a femtosecond laser. ICRSThe effectiveness was assessed on the basis of an increase in uncorrected and corrected visual acuity in the postoperative period, as well as the absence of keratectasia progression in the period from 10 to 18 months after ICRS implantation. Results. All ICRS were implanted in 16 eyes without intra and postoperative complications. Uncorrected distance visual acuity (UDVA) increased from 0.16 ± 0.12 preoperatively to 0.54 ± 0.24 at the 6th month of postoperative follow-up. Corrected distance visual acuity (CDVA) increased from 0.38 ± 0.2 to 0.72 ± 0.34 at the 6th month of postoperative follow-up. The refractive index decreased from preoperative mean –3.56 ± 2.4 D to –2.02 ± 1.4D at the 6th month of postoperative follow-up. The average maximum value of the K index decreased from the preoperative 54.60 ± 3.25 D (in the range from 46.25 to 64.50 D) to the 6-month postoperative value of 45.54 ± 2.72D. Conclusions. The implantation of OCRS in eyes with keratoconus stage II-III with irregular asymmetric paracentral astigmatism is an effective and safe method of increasing visual acuity and reducing refractive errors. Keywords: keratoconus, intrastromal corneal ring segments