2nd Edition IC3D classification of corneal dystrophies

15th February 2016
granular dystrophy
Cited from the original paper
To update the 2008 International Classification of Corneal Dystrophies (IC3D) incorporating new clinical, histopath-ologic, and genetic information.
The IC3D reviewed worldwide peer-reviewed articlesfor 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.
On the basis of revisiting the cellular origin of corneal dystrophy, a modified anatomic classification is proposed consist-ing of (1) epithelial and subepithelial dystrophies, (2) epithelial–stromal TGFBI dystrophies, (3) stromal dystrophies, and (4) endothelial dystrophies. Most of the dystrophy templates areupdated. The entity “Epithelial recurrent erosion dystrophies”actually includes a number of
pot entially distinct epithelial dystrophies (Franceschetti corneal dystrophy, Dystrophia Smolan-
diensis, 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 tocontinue 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.
This revision of the IC3D classification includes anupdated anatomic classification of corneal dystrophies more accu-rately 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
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