title: Intrastromal corneal ring segments implantation in patients with keratoconus: 10-year follow-up.
abstract: OBJECTIVE
  To evaluate the long-term safety and efficacy of Ferrara intrastromal corneal ring segments (ICRS) (Ferrara Ring; AJL, Boecillo, Spain) in patients with keratoconus.
  
  
  METHODS
  The chart records of 36 eyes of 30 patients with keratoconus implanted with ICRS, operated on between July 1996 and January 2002, were retrospectively reviewed. The following parameters were studied: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry (K), and central corneal thickness. The outcomes were evaluated at 5 and 10 years after ICRS implantation.
  
  
  RESULTS
  The mean UDVA (logMAR) improved from 1.01 ± 0.28 (20/200 Snellen) to 0.71 ± 0.38 (20/100 Snellen) at 5 years (P < .05) and 0.67 ± 0.25 (20/90 Snellen) at 10 years (P = .735). The mean CDVA (logMAR) improved from 0.45 ± 0.45 (20/55 Snellen) to 0.24 ± 0.19 (20/35 Snellen) at 5 years (P < .05) and 0.29 ± 0.09 (20/38 Snellen) at 10 years (P = .292). The mean maximum K value decreased from 54.99 ± 6.33 to 50.58 ± 5.11 D at 5 years (P < .05) and 50.65 ± 5.17 D at 10 years (P = .854). The mean minimum K value decreased from 48.85 ± 5.70 to 46.90 ± 5.08 D at 5 years (P < .05) and 47.12 ± 4.22 D at 10 years (P = .945). The central corneal thickness decreased from 457.42 ± 58.21 to 421.34 ± 74.12 μm at 5 years (P = .039) and 434.32 ± 77.65 μm at 10 years (P = .427).
  
  
  CONCLUSIONS
  Intrastromal corneal ring segments can effectively improve UDVA and CDVA 10 years after implantation in patients with keratoconus.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Torquetti
authors.forename: Guilherme
authors.initials: G
authors.lastname: Ferrara
authors.forename: Franklin
authors.initials: F
authors.lastname: Almeida
authors.forename: Leandro
authors.initials: L
authors.lastname: Cunha
authors.forename: Luana P N
authors.initials: LP
authors.lastname: Araujo
authors.forename: Aydano  P
authors.initials: A
authors.lastname: Machado
authors.forename: João
authors.initials: J
authors.lastname: Marcelo Lyra
authors.forename: Jesús
authors.initials: J
authors.lastname: Merayo-Lloves
authors.forename: Paulo
authors.initials: P
authors.lastname: Ferrara
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000503:physiopathology; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology
chemical_list: D019904:Polymethyl Methacrylate