title: Intrastromal corneal ring segment SK implantation for moderate to severe keratoconus.
abstract: OBJECTIVE
  To report the efficacy and safety of intrastromal corneal ring segment (ICRS) implantation using a femtosecond laser in the management of advanced keratoconus.
  
  
  METHODS
  Private laser center, Toronto, Ontario, Canada.
  
  
  METHODS
  In this retrospective nonrandomized study, Intacs SK ICRS were implanted using an IntraLase femtosecond laser in eyes with moderate to severe keratoconus. Evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, slitlamp examination, corneal topography, and wavefront analysis of higher-order aberrations. Postoperative visits were at 1, 7, and 30 days and 3 and 6 months.
  
  
  RESULTS
  The study evaluated 10 eyes of 8 patients with a mean age of 28 years (range 21 to 42 years). The mean UDVA was significantly better 6 months postoperatively than preoperatively (0.66 logMAR +/- 0.21 [SD] versus 1.19 +/- 0.57 logMAR) (P = .004), as was the mean CDVA (0.25 +/- 0.15 logMAR versus 0.51 +/- 0.20 logMAR) (P = .018). The mean spherical equivalent refractive error was -8.08 diopters (D) preoperatively and -5.03 D at 6 months (P = .65); the mean refractive astigmatism, -5.05 D and -3.90 D, respectively (P = .22); and the mean simulated keratometry value, 57.94 D and 50.07 D, respectively (P = .15). The mean total aberration improved significantly, from 13.48 +/- 4.64 mum preoperatively to 9.42 +/- 1.80 mum postoperatively (P = .007). There were no complications.
  
  
  CONCLUSIONS
  Implantation of ICRS for advanced keratoconus was safe and effective, leading to significant improvement in UDVA, CDVA, and total aberrations.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Ontario, Canada. wiwans@hotmail.com
authors.forename: Wiwan
authors.initials: W
authors.lastname: Sansanayudh
authors.forename: Irit
authors.initials: I
authors.lastname: Bahar
authors.forename: Nikhil L
authors.initials: NL
authors.lastname: Kumar
authors.forename: Raneen
authors.initials: R
authors.lastname: Shehadeh-Mashour
authors.forename: Rusty
authors.initials: R
authors.lastname: Ritenour
authors.forename: Neera
authors.initials: N
authors.lastname: Singal
authors.forename: David S
authors.initials: DS
authors.lastname: Rootman
mesh_terms: D057128:Aberrometry; D000328:Adult; D003319:Corneal Stroma / Q000503:physiopathology / Q000601:surgery*; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult