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In 2015, the first revision of the international classification of corneal dystrophies (IC3D) has been published. According to this latest version of the IC3D the dystrophies of the cornea are divided into · epithelial and subepithelial dystrophies,. · epithelial-stromal TGFBI dystrophies,. · stromal dystrophies, and. · Descemet-membrane and endothelial dystrophies.. This article summarizes the epithelial and subepithelial dystrophies of the cornea, which, according to IC3D are the following: · epithelial basement membrane dystrophy (EBMD),. · epithelial recurrent erosion dystrophy (ERED),. · subepithelial mucinous corneal dystrophy (SMCD),. · Meesmann corneal dystrophy (MECD),. · Lisch epithelial corneal dystrophy (LECD),. · gelatinous drop-like corneal dystrophy (GDLD).. The main problem concerning almost all dystrophies of the corneal epithelium are epithelial defects (erosion) associated with pain, epiphora and red eyes. In addition, all dystrophies of the epithelium tend to relapse.While therapy is usually initiated with topical therapeutics, in the course of the disease invasive procedures like phototherapeutic keratectomy (PTK) (possibly with the administration of mitomycin C) or in severe cases even keratoplasty (preferably as deep anterior lamellar keratoplasty; DALK) have to be used. Due to the origin of the disease in the epithelial stem cells at the limbus, the replacement of these cells can also be discussed.

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. PURPOSE: 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 welldefined 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 . KEY WORDS: corneal dystrophy, inherited corneal disease, genetic corneal disease, corneal histopathology, gene, mutation, key reference, eponym, epithelial basement membrane dystrophy, epithelial recurrent erosion dystrophy, subepithelial mucinous corneal dystrophy, Meesmann corneal dystrophy, Lisch epithelial corneal dystrophy, gelatinous drop-like corneal dystrophy, Grayson-Wilbrandt corneal dystrophy, lattice corneal dystrophy, lattice gelsolin type dystrophy, granular corneal dystrophy 1, granular corneal dystrophy 2, Avellino corneal dystrophy, Reis-Bucklers corneal dystrophy, Thiel-Behnke corneal dystrophy, macular corneal dystrophy, Schnyder corneal dystrophy, Schnyder crystalline corneal dystrophy, congenital stromal corneal dystrophy, fleck corneal dystrophy, posterior amorphous corneal dystrophy, central cloudy dystrophy of Francxois, pre-Descemet corneal dystrophy, Fuchs endothelial corneal dystrophy, posterior polymorphous corneal dystrophy, congenital hereditary endothelial dystrophy 1, congenital hereditary endothelial dystrophy 2, X-linked endothelial corneal dystrophy

In pursuance of the IC3D classification the group of the anterior corneal dystrophies include: Epithelial and Subepithelial Dystrophies: (( Epithelial basement membrane dystrophy (EBMD)—majority degenerative, some C1; Epithelial recurrent erosion dystrophy (ERED) C4, (Smolandiensis variant) C3;Subepithelial mucinous corneal dystrophy (SMCD) C4; Mutation in keratin genes: Meesmann corneal dystrophy (MECD) C1; Lisch epithelial corneal dystrophy (LECD) C2; Gelatinous drop-like corneal dystrophy (GDLD) C10 and Bowman Layer Dystrophies: (( Reis–Bucklers corneal dystrophy (RBCD)—Granular corneal dystrophy type 3 C1;Thiel–Behnke corneal dystrophy (TBCD) C1, potential variant C2; Grayson –Wilbrandt corneal dystrophy (GWCD) C4). Foregoing course summarizes genetic background, invasive examination (histological, confocal) and non invasive modern visualization techniques such as AS SOCT. Above lecture will also assume clinical approach.

Background: The recent availability of genetic analyses has demonstrated the shortcomings of the current phenotypic method of corneal dystrophy classification. Abnormalities in different genes call Cause a single phenotype, whereas different defects in a single gene can Cause different phenotypes. Sonic disorders termed corneal dystrophies do not appear to have a genetic basis. Purpose: 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 I 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 imitations 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 call be retrieved on the website www.corneasociety.org/ic3d.

We describe a family with an unusual autosomal dominant anterior corneal dystrophy. The onset was characterized by frequent, recurrent corneal erosions in the first decade. This subsided during adolescence and was followed by progressive decreased vision. Slit-lamp examination revealed bilateral subepithelial opacities and haze, involving the entire cornea, but most dense centrally. Histopathological study revealed a subepithelial band of eosinophilic, periodic acid-Schiff-positive, alcian blue-positive, hyaluronidase-sensitive material anterior to Bowman's layer. Electron microscopy demonstrated subepithelial deposition of fine fibrillar material consistent with glycosaminoglycan. Immunohistochemical analysis indicated that the accumulated material contained a combination of chondroitin 4-sulfate and dermatan sulfate. This unique condition clinically resembled Grayson-Wilbrandt dystrophy, but differed histochemically. To our knowledge, this anterior corneal dystrophy has not previously been reported, and it is best described by the name "subepithelial mucinous corneal dystrophy."