title: Evaluation of intrastromal corneal ring segments for treatment of keratoconus with a mechanical implantation technique.
abstract: OBJECTIVE
  To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation in patients with keratoconus using a mechanical implantation technique.
  
  
  METHODS
  Thirty eyes of 17 patients with keratoconus were enrolled. ICRSs (Keraring) were implanted after 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 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 1.36 ± 0.64 logMAR. At 12 months, the mean UDVA was 0.51 ± 0.28 logMAR (P = 0.001), and the mean preoperative CDVA was 0.57 ± 0.29 logMAR, which improved to 0.23 ± 0.18 (P = 0.001) at 1 year. There was a significant reduction in spherical equivalent refractive error from -6.42 ± 4.69 diopters (D) preoperatively to -1.26 ± 1.45 D (P = 0.001) at 1 year. In the same period, the mean K-readings improved from 49.38 ± 3.72 D to 44.43 ± 3.13 D (P = 0.001), and the mean ISAI improved from 7.92 ± 3.12 to 4.21 ± 1.96 (P = 0.003). No significant changes in mean central corneal thickness were observed postoperatively. There were no major complications during and or after surgery.
  
  
  CONCLUSIONS
  ICRS implantation using a unique mechanical dissection technique is a safe and effective treatment for keratoconus. All parameters improved by the 1-year follow-up.
authors.affiliation: Department of Ophthalmology, Maltepe University School of Medicine, Istanbul, Turkey.
authors.forename: Zeki
authors.initials: Z
authors.lastname: Tunc
authors.forename: Firat
authors.initials: F
authors.lastname: Helvacioglu
authors.forename: Sadik
authors.initials: S
authors.lastname: Sencan
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D019781:Corneal Topography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000379:methods*; D012029:Refraction, Ocular; D016896:Treatment Outcome