Fuchs' dystrophy

Fuchs dystrophy, also referred to as Fuchs endothelial corneal dystrophy (FECD) and Fuchs endothelial dystrophy (FED), is a slowly progressing corneal dystrophy that usually affects both eyes and is slightly more common in women than in men. Although early signs of Fuchs dystrophy are sometimes seen in people in their 30s and 40s, the disease rarely affects vision until people reach their 50s and 60s. As a progressive, chronic condition, signs and symptoms of Fuchs dystrophy gradually progress over decades of life, starting in middle age. Early symptoms include blurry vision upon wakening which improves during the morning, as fluid retained in the cornea is unable to evaporate through the surface of the eye when the lids are closed overnight. As the disease worsens, the interval of blurry morning vision extends from minutes to hours. In moderate stages of the disease, an increase in guttae and swelling in the cornea can contribute to changes in vision and decreased sharpness throughout the day. Contrast sensitivity may be affected. The change in the refractive index of the cornea may result in subtle refractive shifts, which affected individuals may experience as a small change in their eyeglass prescription. In the late stages of the disease, the cornea is unable to maintain its fluid content and blisters, known as bullae, form on the surface of the cornea. These cause foreign body sensations and can be painful. The cornea may not heal from such epithelial defects, until corneal transplantation is able to restore the endothelial pump function. FECD is a degenerative disease of the corneal endothelium with accumulation of focal outgrowths called guttae (drops) and thickening of Descemet's membrane, leading to corneal edema and loss of vision. The corneal endothelial cell layer and its basement membrane (Descemet's membrane) act as a barrier to hydration of the corneal stroma by aqueous humor and are "pump" cells of the cornea that function to maintain hydration of the cornea at a specific level that maintains corneal stromal clarity through precise spatial arrangement of collagen fibers.