title: Comparison of mechanical and femtosecond laser tunnel creation for intrastromal corneal ring segment implantation in keratoconus: prospective randomized clinical trial.
abstract: OBJECTIVE
  To compare the outcomes of mechanical and femtosecond laser-assisted tunnel creation for intrastromal corneal ring segment (ICRS) implantation in eyes with keratoconus.
  
  
  METHODS
  Kartal Training and Research Hospital, Istanbul, Turkey.
  
  
  METHODS
  In this prospective study, consecutive eyes with keratoconus were randomly assigned to have ICRS tunnel creation with a mechanical device or a femtosecond laser. Keraring ICRS with a 5.0 mm diameter and 160-degree arc length were implanted in all cases. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, and keratometry (K) readings were measured preoperatively and 1 year postoperatively, and the data in the mechanical group and the femtosecond group were compared statistically.
  
  
  RESULTS
  One year postoperatively, there was significant improvement in UDVA, CDVA, K readings, spherical equivalent (SE), and manifest sphere and cylinder in both groups (P<.05). The UDVA improved by 2.4 lines in the mechanical group and 2.0 lines in the femtosecond group and the CDVA by 3.3 lines and 2.7 lines, respectively; the mean reduction in maximum keratometry was 4.50 diopters (D) and 4.70 D, respectively, and the mean reduction in SE, 3.18 D and 3.09 D, respectively. There were no statistically significant differences between the 2 groups in visual or refractive results (P>.05). Anterior corneal perforation, superficial segment placement, and segment extrusion occurred in 1 eye each in the mechanical group. Segment migration occurred in 1 eye in the femtosecond group.
  
  
  CONCLUSIONS
  Despite intraoperative complications in the mechanical group, the visual and refractive outcomes were similar to those in the femtosecond group.
authors.affiliation: Kartal Training and Research Hospital, Istanbul, Turkey.
authors.forename: Anil
authors.initials: A
authors.lastname: Kubaloglu
authors.forename: Esin Sogutlu
authors.initials: ES
authors.lastname: Sari
authors.forename: Yasin
authors.initials: Y
authors.lastname: Cinar
authors.forename: Kürşat
authors.initials: K
authors.lastname: Cingu
authors.forename: Arif
authors.initials: A
authors.lastname: Koytak
authors.forename: Erol
authors.initials: E
authors.lastname: Coşkun
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Ozertürk
mesh_terms: D000293:Adolescent; D000328:Adult; D003319:Corneal Stroma / Q000601:surgery*; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D007640:Keratoconus / Q000601:surgery*; D053685:Laser Therapy; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D013508:Ophthalmologic Surgical Procedures; D019904:Polymethyl Methacrylate; D011183:Postoperative Complications; D011446:Prospective Studies; D019736:Prostheses and Implants; D019919:Prosthesis Implantation / Q000379:methods*; D012029:Refraction, Ocular / Q000502:physiology; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D019904:Polymethyl Methacrylate