title: Causes of intrastromal corneal ring segment explantation: clinicopathologic correlation analysis.
abstract: OBJECTIVE
  To determine the main causes of intrastromal corneal ring segment (ICRS) explantation and the relationship with the microscopic findings on the ICRS surface.
  
  
  METHODS
  Vissum Corporation-Instituto Oftalmológico de Alicante, Alicante, Spain.
  
  
  METHODS
  This study evaluated ICRS that were explanted in centers in Spain from 2000 to 2008. Clinical data (reasons for explantation, date of implantation/explantation, tunnel creation technique, ICRS type) and scanning electron microscopy findings on the ICRS surface (adherent tissue-like material, cell deposits, protein) were documented.
  
  
  RESULTS
  Intrastromal corneal ring segments were explanted from 58 eyes (47 patients). The main cause was extrusion (48.2% of explanted segments), followed by refractive failure (ie, poor refractive outcome) (37.9%), keratitis (6.8%; 3.7% culture positive), and corneal melting and perforation (6.8%). Scanning electron microscopy showed cells and cell debris on the ICRS explanted by extrusion, a clean surface on the ICRS explanted for refractive failure, and bacteria (cocci) in the case of proven infectious keratitis.
  
  
  CONCLUSIONS
  The main cause of explantation was extrusion of the ICRS followed by refractive failure. There was a clear correlation between the cause of explantation and the microscopic findings on the ICRS. Extrusion was accompanied by inflammatory cells and cell debris on the ICRS surface. No inflammatory reaction was observed on the ICRS explanted for refractive failure.
authors.affiliation: Vissum Corporation-Instituto Oftalmológico de Alicante, Division of Ophthalmology, Universidad Miguel Hernandez, Alicante, Spain. cferrer@vissum.com
authors.forename: Consuelo
authors.initials: C
authors.lastname: Ferrer
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Alió
authors.forename: Antonio Uceda
authors.initials: AU
authors.lastname: Montañés
authors.forename: Jose J
authors.initials: JJ
authors.lastname: Pérez-Santonja
authors.forename: Miguel A Diaz
authors.initials: MA
authors.lastname: del Rio
authors.forename: Juan Alvarez
authors.initials: JA
authors.lastname: de Toledo
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Teus
authors.forename: Jaime
authors.initials: J
authors.lastname: Javaloy
mesh_terms: D000293:Adolescent; D000328:Adult; D003316:Corneal Diseases / Q000601:surgery*; D003319:Corneal Stroma / Q000601:surgery*; D020878:Device Removal; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants / Q000382:microbiology / Q000648:ultrastructure*; D011475:Prosthesis Failure; D019919:Prosthesis Implantation; D055815:Young Adult
chemical_list: D019904:Polymethyl Methacrylate