title: Implantation of a complete corneal ring in an intrastromal pocket for keratoconus.
abstract: OBJECTIVE
  to evaluate the refractive and visual results of a new treatment for keratoconus using the corneal intrastromal implantation system (CISIS).
  
  
  METHODS
  six eyes of four patients with keratoconus were treated with CISIS. Follow-up was 1, 3, and 6 months. After creating an intracorneal pocket of 9-mm diameter and 300-microm depth, a flexible full-ring implant was inserted via a 4-mm-wide corneal tunnel.
  
  
  RESULTS
  no eyes showed loss of lines in uncorrected distance visual acuity (UDVA) or spectacle corrected distance visual acuity (CDVA) at any follow-up examination. Uncorrected and distance corrected visual acuity, keratometry, spherical and cylindrical refractive error as well as spherical equivalent refraction improved significantly (P<.05). Mean UDVA improved from 20/260 to 20/48 and mean CDVA improved from 20/41 to 20/27. A significant centralization and decrease of the corneal apex was found. No intra- or postoperative complications were observed.
  
  
  CONCLUSIONS
  the corneal intrastromal implantation system using a complete ring implanted in a stromal pocket can achieve significant improvements in the visual function of patients with keratoconus. Uncorrected distance visual acuity improved by more than seven lines on average and CDVA improved by two lines.
authors.affiliation: Eye Specialist Center, Manama, Kingdom of Bahrain.
authors.forename: Haifa
authors.initials: H
authors.lastname: Mahmood
authors.forename: R S
authors.initials: RS
authors.lastname: Venkateswaran
authors.forename: Albert
authors.initials: A
authors.lastname: Daxer
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000503:physiopathology / Q000601:surgery*; D019781:Corneal Topography; D005500:Follow-Up Studies; D006801:Humans; D007431:Intraoperative Complications; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D019904:Polymethyl Methacrylate; D011183:Postoperative Complications; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D019904:Polymethyl Methacrylate