title: Intrastromal corneal ring--one-year results of first implants in humans: a preliminary nonfunctional eye study.
abstract: BACKGROUND
  The Intrastromal Corneal Ring (ICR) is a new investigational medical device designed to alter corneal curvature without surgical intervention in the central cornea. The ring is inserted between the layers of the stroma in the cornea's periphery at two-thirds depth through an approximately 2-millimeter incision.
  
  
  METHODS
  To investigate the safety and refractive effect of implanting an ICR of a given thickness (0.30 mm) and outer diameter (7.70 mm) into human corneas, an ICR was implanted into one nonfunctional eye of each of three patients during the period of March to May, 1991. One predesignated ICR was successfully explanted 5 months after implantation to evaluate the feasibility of ICR removal and to observe the effect of ring removal on corneal curvature. Patients were followed for 1 year after the initial implant procedure.
  
  
  RESULTS
  The three implant procedures and postoperative courses proceeded without any significant complications. Approximately 2.00 D of central corneal flattening was achieved in all eyes. No adverse reactions or other medically-significant complications were observed over a 1-year follow-up period. The patient who underwent ICR removal experienced no perioperative complications, and the patient's cornea has remained stable with a return to its preoperative curvature.
  
  
  CONCLUSIONS
  Although this study is preliminary and limited in scope, we have demonstrated that the ICR can be tolerated safely in the human cornea and results in a flattening of the corneal curvature that is stable for up to a year after insertion. The successful removal of the ICR begins to establish reversibility of the procedure and induced refractive effect.
authors.affiliation: Department of Ophthalmology, Escola Paulista de Medicina, São Paulo Hospital, Brazil.
authors.forename: W
authors.initials: W
authors.lastname: Nosé
authors.forename: R A
authors.initials: RA
authors.lastname: Neves
authors.forename: D J
authors.initials: DJ
authors.lastname: Schanzlin
authors.forename: R
authors.initials: R
authors.lastname: Belfort Júnior
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000601:surgery*; D005123:Eye / Q000503:physiopathology; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D020366:Methylmethacrylate; D008768:Methylmethacrylates; D009216:Myopia / Q000601:surgery*; D010865:Pilot Projects; D011183:Postoperative Complications; D019736:Prostheses and Implants; D011474:Prosthesis Design; D016896:Treatment Outcome
chemical_list: D008768:Methylmethacrylates; D020366:Methylmethacrylate