- Fuchs (pronounced Fooks) endothelial corneal dystrophy is a bilateral, progressive, noninflammatory disease of the eye characterized by endothelial dysfunction, leading to corneal edema and vision loss.
- Keratoplasty (full- or partial-thickness corneal transplant) is the definitive management step for restoration of vision.
- Typically presents in the 5th and 6th decades, with rare early-onset Fuchs dystrophy in the 1st decade of life
- The leading indication for corneal transplant in the United States
- Accounts for >15,000 cases of keratoplasty in the most recent year (1)
- Women appear more susceptible than men, 3 to 4:1.
- 5% of the U.S. population >40 years old (2)
Etiology and Pathophysiology
- The cornea provides 74% of the refractive power of the human eye and is composed of five layers: epithelium, Bowman layer, stroma, Descemet membrane, and endothelium.
- The endothelium provides vital barrier and ion transport functions, enabled by Na+/K+ ATPase pumps, which regulate corneal hydration and transparency.
- Attrition of endothelial cells accompanies normal aging: Endothelial cell density averages 2,400 cells/mm2 in adults, contrasted with 6,000 cells/mm2 in infants.
- Endothelial cell density is also adversely impacted by intraocular insults, notably cataract surgery and elevated intraocular pressure (IOP).
- In Fuchs dystrophy, endothelial stress manifests as endothelial cell morphologic changes and decreased cellular density, abnormal deposition of collagen and extracellular matrix in Descemet membrane, resulting in progressive stromal edema.
- Changes in Descemet membrane can be visualized microscopically as thickening and characteristic anvil-shaped refractive granules known as guttae (Latin: drops) which are first visible in the central cornea and spread progressively toward the periphery.
- As endothelial barrier and ion transport functions are increasingly overwhelmed, endothelial cell attrition accelerates and the central cornea becomes grossly thickened.
- Epithelial edema develops late in the disease course, associated with painful epithelial bullae, subepithelial fibrosis, and superficial corneal neovascularization.
- Most commonly presents without known inheritance (category 3)
- Late-onset familial and sporadic cases less commonly are linked to genetic loci (category 2).
- Several chromosomal loci on 1, 5, 7, 9, 13, 15, 17, and X chromosomes have been implicated, with both autosomal dominant and complex inheritance patterns (3).
- Early-onset variant genetic locus (category 1)
- 1p34.3–p32, associated with collagen type VIII α2 (COL8A2) gene
- Age >50 years
- Female gender
- Family history of Fuchs dystrophy
Commonly Associated Conditions
- Bullous keratopathy
- Angle-closure glaucoma
- Open-angle glaucoma
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