title: Ferrara intracorneal ring segments for keratoconus.
abstract: OBJECTIVE
  To assess the outcome of Ferrara intracorneal ring segments for keratoconus.
  
  
  METHODS
  Private practice and university hospital, Porto Alegre, Brazil.
  
  
  METHODS
  In this retrospective noncomparative interventional case series, 51 keratoconus eyes of 47 patients that had Ferrara intracorneal ring segment implantation were reviewed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), central corneal curvature, corneal astigmatism, surface regularity index, surface asymmetry index, and complications were analyzed.
  
  
  RESULTS
  At a mean follow-up of 13.0 months +/- 8.7 (SD), the BSCVA improved in 86.4% of eyes, was unchanged in 1.9%, and worsened in 11.7%. The UCVA improved in 86.4% of eyes, was unchanged in 7.8%, and worsened in 5.8%. The mean spherical equivalent (SE) was reduced from -6.08 +/- 5.01 diopters (D) to -4.55 +/- 5.71 D and the mean refractive astigmatism, from -3.82 +/- 2.13 D to -2.16 +/- 2.07 D. The mean central corneal curvature was reduced from 48.76 +/- 3.97 D to 43.17 +/- 4.79 D. Eyes with central keratoconus had statistically significantly better results than eyes with inferior keratoconus in topographic astigmatism, SE, and refraction cylinder. Penetrating keratoplasty was avoided in 38 eyes (74.5%) during the follow-up. Intracorneal ring segment decentration occurred in 2 eyes (3.9%), segment extrusion in 10 eyes (19.6%), bacterial keratitis in 1 eye (1.9%) with segment extrusion, and a disciform keratitis in 1 eye (1.9%).
  
  
  CONCLUSIONS
  Implantation of Ferrara intracorneal ring segments in patients with keratoconus was a safe and reversible procedure that led to stable results and avoided or delayed PKP in many cases.
authors.affiliation: Department of Ophthalmology, Hospital de Clínicas de Porto Alegre, Avenida Nilo Peçanha, 7241-401 Porto Alegre-RS, Brazil. Kwitko@ez-poa.com.br
authors.forename: Sérgio
authors.initials: S
authors.lastname: Kwitko
authors.forename: Nórton Souto
authors.initials: NS
authors.lastname: Severo
mesh_terms: D001251:Astigmatism; D001672:Biocompatible Materials; D003319:Corneal Stroma / Q000601:surgery*; D019781:Corneal Topography; D006801:Humans; D007431:Intraoperative Complications; D007640:Keratoconus / Q000601:surgery*; D019904:Polymethyl Methacrylate; D011183:Postoperative Complications; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012189:Retrospective Studies; D012449:Safety; D014792:Visual Acuity
chemical_list: D001672:Biocompatible Materials; D019904:Polymethyl Methacrylate