title: Clinical outcomes after implantation of a new intrastromal corneal ring with a 210-degree arc length.
abstract: OBJECTIVE
  To report the clinical outcomes of implantation of a new Ferrara intrastromal corneal ring segment (ICRS) with a 210-degree arc length in eyes with keratoconus.
  
  
  METHODS
  Private eye clinic, Belo Horizonte, Brazil
  
  
  METHODS
  Statistical analysis included preoperative and postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, and keratometry.
  
  
  RESULTS
  Eighty eyes (76 patients) were evaluated. The UDVA improved from 20/350 preoperatively to 20/136 postoperatively and the CDVA, from 20/125 to 20/50; the differences were statistically significant (P = .001 and P = .0001, respectively). Corneal tomography (Pentacam) showed corneal flattening in all eyes. The mean preoperative spherical equivalent decreased from -5.22 diopters (D) preoperatively to -2.26 D postoperatively (P = .050); the mean keratometry (K) 1 value, from 51.49 D to 47.40 D (P = .00014); and the mean K2 value, from 54.33 D to 49.14 D (P = .00022). Two patients required penetrating keratoplasty despite ICRS implantation.
  
  
  CONCLUSIONS
  A new ICRS with 210 degrees of arc was effective in treating keratoconus. It improved visual acuity and reduced corneal steepening in selected patients.
authors.affiliation: pferrara@ferrararing.com.br
authors.forename: Paulo
authors.initials: P
authors.lastname: Ferrara
authors.forename: Leonardo
authors.initials: L
authors.lastname: Torquetti
mesh_terms: D003319:Corneal Stroma / Q000503:physiopathology / Q000601:surgery*; D019781:Corneal Topography; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants; D011474:Prosthesis Design; D019919:Prosthesis Implantation; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology
chemical_list: D019904:Polymethyl Methacrylate