title: Intrastromal corneal ring segments to correct low myopia in eyes with irregular or abnormal topography including forme fruste keratoconus: 4-year follow-up.
abstract: OBJECTIVE
  To report the 4-year outcomes after Intacs intrastromal corneal ring segment (ICRS) implantation to correct low myopia in patients with abnormal topography.
  
  
  METHODS
  Instituto de Microcirugia Ocular, Barcelona, Spain.
  
  
  METHODS
  This retrospective consecutive interventional case series included eyes with myopia lower than -4.50 diopters (D) and abnormal topography that excluded excimer laser surgery. Evaluation was performed preoperatively and at yearly intervals up to 4 years postoperatively. The 4-year outcomes measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, predictability and stability of refractive correction, the efficacy and safety indices, and complications.
  
  
  RESULTS
  After ICRS implantation, 82.05% of 39 eyes (21 patients) were within +/-1.00 diopter (D) of emmetropia and 46.15% were within +/-0.50 D. Refractive correction improved during the first 6 months and remained stable up to 4 years. The UDVA was 20/40 or better in all eyes and 20/20 or better in 38.46% of eyes. Seven eyes (17.95%) lost 1 line of CDVA, and no eye lost 2 or more lines. No intraoperative complications occurred. The ICRS were exchanged for thicker ICRS in 7 eyes (17.9%) because of undercorrection. One patient requested ICRS removal due to unsatisfactory refractive results.
  
  
  CONCLUSIONS
  The 4-year results indicate that ICRS implantation is effective and safe in the correction of low myopia in patients for whom excimer laser surgery is contraindicated because of abnormal topography, including forme fruste keratoconus. The achieved refractive correction remained stable throughout the follow-up.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Ophthalmology Department, Universitat Autonoma de Barcelona, Cornea and Refractive Surgery Unit, Barcelona, Spain guell@imo.es
authors.forename: José L
authors.initials: JL
authors.lastname: Güell
authors.forename: Merce
authors.initials: M
authors.lastname: Morral
authors.forename: Cecilia
authors.initials: C
authors.lastname: Salinas
authors.forename: Daniel
authors.initials: D
authors.lastname: Elies
authors.forename: Oscar
authors.initials: O
authors.lastname: Gris
authors.forename: Felicidad
authors.initials: F
authors.lastname: Manero
mesh_terms: D000293:Adolescent; D000328:Adult; D003319:Corneal Stroma / Q000601:surgery*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D007640:Keratoconus / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D019904:Polymethyl Methacrylate