title: [The IC3D classification of the corneal dystrophies].
abstract: BACKGROUND
  The recent availability of genetic analyses has demonstrated the shortcomings of the current phenotypic method of corneal dystrophy classification. Abnormalities in different genes can cause a single phenotype, whereas different defects in a single gene can cause different phenotypes. Some disorders termed corneal dystrophies do not appear to have a genetic basis.
  
  
  OBJECTIVE
  The purpose of this study was to develop a new classification system for corneal dystrophies, integrating up-to-date information on phenotypic description, pathologic examination, and genetic analysis.
  
  
  METHODS
  The International Committee for Classification of Corneal Dystrophies (IC3D) was created to devise a current and accurate nomenclature.
  
  
  RESULTS
  This anatomic classification continues to organize dystrophies according to the level chiefly affected. Each dystrophy has a template summarizing genetic, clinical, and pathologic information. A category number from 1 through 4 is assigned, reflecting the level of evidence supporting the existence of a given dystrophy. The most defined dystrophies belong to category 1 (a well-defined corneal dystrophy in which a gene has been mapped and identified and specific mutations are known) and the least defined belong to category 4 (a suspected dystrophy where the clinical and genetic evidence is not yet convincing). The nomenclature may be updated over time as new information regarding the dystrophies becomes available.
  
  
  CONCLUSIONS
  The IC3D Classification of Corneal Dystrophies is a new classification system that incorporates many aspects of the traditional definitions of corneal dystrophies with new genetic, clinical, and pathologic information. Standardized templates provide key information that includes a level of evidence for there being a corneal dystrophy. The system is user-friendly and upgradeable and can be retrieved on the website www.corneasociety.org/ic3d .
authors.affiliation: Kresge Eye Institute, Departments of Ophthalmology and Pathology, Wayne State University School of Medicine, Detroit, Michigan, USA. jweiss@med.wayne.edu
authors.forename: J S
authors.initials: JS
authors.lastname: Weiss
authors.forename: H U
authors.initials: HU
authors.lastname: Møller
authors.forename: W
authors.initials: W
authors.lastname: Lisch
authors.forename: S
authors.initials: S
authors.lastname: Kinoshita
authors.forename: A J
authors.initials: AJ
authors.lastname: Aldave
authors.forename: M W
authors.initials: MW
authors.lastname: Belin
authors.forename: T
authors.initials: T
authors.lastname: Kivelä
authors.forename: M
authors.initials: M
authors.lastname: Busin
authors.forename: F L
authors.initials: FL
authors.lastname: Munier
authors.forename: B
authors.initials: B
authors.lastname: Seitz
authors.forename: J
authors.initials: J
authors.lastname: Sutphin
authors.forename: C
authors.initials: C
authors.lastname: Bredrup
authors.forename: M J
authors.initials: MJ
authors.lastname: Mannis
authors.forename: C
authors.initials: C
authors.lastname: Rapuano
authors.forename: G
authors.initials: G
authors.lastname: Van Rij
authors.forename: E K
authors.initials: EK
authors.lastname: Kim
authors.forename: G K
authors.initials: GK
authors.lastname: Klintworth
mesh_terms: D003317:Corneal Dystrophies, Hereditary / Q000145:classification* / Q000175:diagnosis / Q000235:genetics*; D003941:Diagnostic Techniques, Ophthalmological; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D038801:International Classification of Diseases; D009626:Terminology as Topic