title: Outcomes of intrastromal corneal ring segments for treatment of keratoconus: five-year follow-up analysis.
abstract: OBJECTIVE
  To report the long-term refractive and optical quality outcomes of patients with intrastromal corneal ring segments (ICRS) to treat keratoconus and to analyze the results according to the patients' age.
  
  
  METHODS
  Vissum Instituto Oftalmologico de Alicante, Alicante, Spain.
  
  
  METHODS
  Case series.
  
  
  METHODS
  The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, corneal topography, and aberrometry were evaluated before and after ICRS implantation in eyes with keratoconus. The follow-up was 5 years in all cases.
  
  
  RESULTS
  The study comprised 51 eyes (35 patients; age range 15 to 56 years). After 6 months, the improvement in the UDVA, CDVA, spherical equivalent, and mean keratometry (K) value was statistically significant (P<.05). Five years postoperatively, these parameters remained unchanged (P=.31). Slight regression (0.97 diopter [D]) was observed in the mean K between 6 months and 5 years; the regression was not statistically significant (P=.39). Anterior corneal aberrometric values decreased; however, the changes were not statistically significant (P ≥.10). Linear regression analysis showed no correlation between the age of the patients and the changes observed in the mean K throughout the follow-up (P>.05, r(2) = 0.001).
  
  
  CONCLUSIONS
  Intrastromal corneal ring segment implantation in keratoconus patients provided long-term improvement of the refractive and topographic status. There was no correlation between the amount of individual changes in the mean K reading and patient age.
authors.affiliation: Keratoconus Unit, Vissum Instituto Oftalmologico de Alicante, Alicante, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Vega-Estrada
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Alió
authors.forename: Luis F
authors.initials: LF
authors.lastname: Brenner
authors.forename: Neus
authors.initials: N
authors.lastname: Burguera
mesh_terms: D057128:Aberrometry; D000293:Adolescent; 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; D008875:Middle Aged; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012029:Refraction, Ocular / Q000502:physiology; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult