title: IC3D classification of corneal dystrophies--edition 2.
abstract: OBJECTIVE
  To update the 2008 International Classification of Corneal Dystrophies (IC3D) incorporating new clinical, histopathologic, and genetic information.
  
  
  METHODS
  The IC3D reviewed worldwide peer-reviewed articles for new information on corneal dystrophies published between 2008 and 2014. Using this information, corneal dystrophy templates and anatomic classification were updated. New clinical, histopathologic, and confocal photographs were added.
  
  
  RESULTS
  On the basis of revisiting the cellular origin of corneal dystrophy, a modified anatomic classification is proposed consisting of (1) epithelial and subepithelial dystrophies, (2) epithelial-stromal TGFBI dystrophies, (3) stromal dystrophies, and (4) endothelial dystrophies. Most of the dystrophy templates are updated. The entity "Epithelial recurrent erosion dystrophies" actually includes a number of potentially distinct epithelial dystrophies (Franceschetti corneal dystrophy, Dystrophia Smolandiensis, and Dystrophia Helsinglandica) but must be differentiated from dystrophies such as TGFBI-induced dystrophies, which are also often associated with recurrent epithelial erosions. The chromosome locus of Thiel-Behnke corneal dystrophy is only located on 5q31. The entity previously designated as a variant of Thiel-Behnke corneal dystrophy on chromosome 10q24 may represent a novel corneal dystrophy. Congenital hereditary endothelial dystrophy (CHED, formerly CHED2) is most likely only an autosomal recessive disorder. The so-called autosomal dominant inherited CHED (formerly CHED1) is insufficiently distinct to continue to be considered a unique corneal dystrophy. On review of almost all of the published cases, the description appeared most similar to a type of posterior polymorphous corneal dystrophy linked to the same chromosome 20 locus (PPCD1). Confocal microscopy also has emerged as a helpful tool to reveal in vivo features of several corneal dystrophies that previously required histopathologic examination to definitively diagnose.
  
  
  CONCLUSIONS
  This revision of the IC3D classification includes an updated anatomic classification of corneal dystrophies more accurately classifying TGFBI dystrophies that affect multiple layers rather than are confined to one corneal layer. Typical histopathologic and confocal images have been added to the corneal dystrophy templates.
authors.affiliation: *Department of Ophthalmology, Pathology and Pharmacology, Louisiana State University Eye Center of Excellence, Louisiana State University Health Sciences Center, Louisiana State University, New Orleans, LA; †Department of Pediatric Ophthalmology, Viborg Hospital and Aarhus University Hospital, Aarhus, Denmark; ‡The Jules Stein Eye Institute, University of California at Los Angeles, Los Angeles, CA; §Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany; ¶Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway; ‖Department of Opthalmology, Helsinki University Central Hospital, Helsinki, Finland; **Jules-Gonin Eye Hospital, Lausanne, Switzerland; ††Cornea Service, Wills Eye Hospital, Philadelphia, PA; ‡‡University of Pittsburgh Medical Center Children's Eye Center, Pittsburgh, PA; §§Cornea Dystrophy Research Institute, Department of Ophthalmology, College of Medicine, Yonsei University, Seoul, Korea; ¶¶Department of Ophthalmology, University of Kansas Medical Center, Kansas City, KS; ‖‖Department of Ophthalmology, Villa Igea Hospital, Maître de Conférences des Universités Praticien Hospitalier, Forli, Italy; ***Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Institut de la Vision, Paris, France; †††Tufts University School of Medicine, Harvard Medical School, Schepens Eye Research Institute, New England Eye Center, Boston, MA; ‡‡‡Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan; and §§§Department of Ophthalmology, Johannes Gutenberg University Mainz, Mainz, Germany.
authors.forename: Jayne S
authors.initials: JS
authors.lastname: Weiss
authors.forename: Hans Ulrik
authors.initials: HU
authors.lastname: Møller
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Aldave
authors.forename: Berthold
authors.initials: B
authors.lastname: Seitz
authors.forename: Cecilie
authors.initials: C
authors.lastname: Bredrup
authors.forename: Tero
authors.initials: T
authors.lastname: Kivelä
authors.forename: Francis L
authors.initials: FL
authors.lastname: Munier
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Rapuano
authors.forename: Kanwal K
authors.initials: KK
authors.lastname: Nischal
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
authors.forename: John
authors.initials: J
authors.lastname: Sutphin
authors.forename: Massimo
authors.initials: M
authors.lastname: Busin
authors.forename: Antoine
authors.initials: A
authors.lastname: Labbé
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Kenyon
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kinoshita
authors.forename: Walter
authors.initials: W
authors.lastname: Lisch
mesh_terms: D003317:Corneal Dystrophies, Hereditary / Q000145:classification* / Q000235:genetics / Q000473:pathology; D006801:Humans; D038801:International Classification of Diseases; D009626:Terminology as Topic