Purpose: The International Committee for the Classification of Corneal Dystrophies (IC3D) was created in 2005 to develop a new classification system integrating current information on phenotype, histopathology, and genetic analysis. This update is the third edition of the IC3D nomenclature. Methods: Peer-reviewed publications from 2014 to 2023 were evaluated. The new information was used to update the anatomic classification and each of the 22 standardized templates including the level of evidence for being a corneal dystrophy [from category 1 (most evidence) to category 4 (least evidence)]. Results: Epithelial recurrent erosion dystrophies now include epithelial recurrent erosion dystrophy, category 1 (COL17A1 mutations, chromosome 10). Signs and symptoms are similar to Franceschetti corneal dystrophy, dystrophia Smolandiensis, and dystrophia Helsinglandica, category 4. Lisch epithelial corneal dystrophy, previously reported as X-linked, has been discovered to be autosomal dominant (MCOLN1 mutations, chromosome 19). Classic lattice corneal dystrophy (LCD) results from TGFBI R124C mutation. The LCD variant group has over 80 dystrophies with non-R124C TGFBI mutations, amyloid deposition, and often similar phenotypes to classic LCD. We propose a new nomenclature for specific LCD pathogenic variants by appending the mutation using 1-letter amino acid abbreviations to LCD. Pre-Descemet corneal dystrophies include category 1, autosomal dominant, punctiform and polychromatic pre-Descemet corneal dystrophy (PPPCD) (PRDX3 mutations, chromosome 10). Typically asymptomatic, it can be distinguished phenotypically from pre-Descemet corneal dystrophy, category 4. We include a corneal dystrophy management table. Conclusions: The IC3D third edition provides a current summary of corneal dystrophy information. The article is available online at https://corneasociety.org/publications/ic3d.

To demonstrate 5 different patterns of immunotactoid keratopathy (ITK) in monoclonal gammopathy of undetermined significance (MGUS) that can mimic hereditary and degenerative disorders. First follow-up of 1 female patient was performed. Colored slit-lamp photodocumentation of 6 MGUS light kappa patients with different types of ITK, one patient with a follow-up of 7 years. Systemic and serological examinations of all 6 patients were performed. The systemic and serological examinations disclosed an MGUS light kappa in all 6 patients. The 7-year follow-up of case 2 showed a reduction of lattice-like opacity to moderate diffuse corneal opacity. Corneal opacity patterns of the 6 patients were as follows: pattern 1, crystalline-like; pattern 2, lattice-like; pattern 3, peripheral granular-like; pattern 4, peripheral band-like; and patterns 5 and 6, peripheral patch-like. ITK of MGUS can mimic cystinosis, Schnyder corneal dystrophy (CD), pre-Descemet CD, lattice CD, granular CD, arcus lipoides, lecithin-cholesterol acyltransferase deficiency, gelatinous drop-like CD, and Salzmann nodular degeneration. ITK can be the first symptom of MGUS. An annual internal check of MGUS is recommended because of occurrence of a systemic monoclonal gammopathy in 20% of cases.