Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) is an eye disease. It affects the thin layer of cells that line the back part of the cornea. This layer is called the endothelium. The disease occurs when these cells slowly start to die off. The cells help pump excess fluid out of the cornea. As more and more cells are lost, fluid begins to build up in the cornea, causing swelling and a cloudy cornea.^[1] There are several forms of the disease according to the age of onset of the symptoms and the cause.

The early-onset form is very rare and is known as Fuchs endothelial corneal dystrophy 1 (or early-onset Fuchs endothelial corneal dystrophy) and it is caused by a change (mutation) in the COL8A2 gene. Late-onset Fuchs endothelial corneal dystrophies are common and include:

• Fuchs endothelial corneal dystrophy 2 (caused by a mutation in an unknown gene located in chromosome 13)
• Fuchs endothelial corneal dystrophy 3 (may be caused by TCF4 gene mutations)
• Fuchs endothelial corneal dystrophy 4 (caused by a mutation in the SLC4A11 gene)
• Fuchs endothelial corneal dystrophy 5 (caused by a mutation in an unknown gene located in chromosome 15)
• Fuchs endothelial corneal dystrophy 6 (caused by a mutation in the ZEB1 gene)
• Fuchs endothelial corneal dystrophy 7 (caused by a mutation in an unknown gene located in chromosome 9)
• Fuchs endothelial corneal dystrophy 8 (caused by heterozygous mutation in the AGBL1 gene). 

Early in the disease, patients typically do not have symptoms. In the late-onset forms, the symptoms start around 50 or 60 years and include discomfort and painful episodes of recurrent corneal wounds and hazy vision. Over time, discomfort may diminish but severe impairment of visual acuity, and even blindness and cataracts in elderly patients, may be observed. Once the vision has worsened, the recommended treatment is a penetrating graft which has excellent results in most cases.^[2]

Diagnosis of Fuchs corneal endothelial dystrophy requires a slit-lamp examination to view the cornea changes that are characteristic for this condition. The earliest observable change suggestive of Fuchs' dystrophy is the presence of guttae. Guttae are bumps on the back surface of the cornea.

Additional tests that may be done include pachymetry to measure the thickness of the cornea, a specular microscope examination to look at the endothelium cells, and a visual acuity test.^[1]

Pachymetry is a good way of gauging the increase in corneal edema. The thickness can be compared with the new readings on subsequent visits. Increasing thickness of the cornea means increasing corneal endothelial decompensation. Presence of Descemet folds, epithelial bedewing, and corneal thickness of greater than 0.62 mm indicates potential decompensation.^[2]

Lattice corneal dystrophy is an eye disorder that affects the stroma. The stroma is the middle layer of the cornea. The cornea is the eye's outermost layer. Click here to view an image of the cornea.^[3]

Lattice corneal dystrophies are characterized by the buildup of a type of protein, known as amyloid in the stroma. Symptoms may include separation between the layers of the cornea (corneal erosions), decreased vision, photosensitivity, and eye pain. Most cases of lattice dystrophy are caused by mutations in the TGFBI gene. Lattice dystrophy type 1 is the most common type of lattice dystrophy.^[3]

Diagnosis of LCD1 is based on the signs and symptoms.^[3] Medscape Reference offers information on the diagnosis of LCD1 as well as the signs and symptoms. To read more, click here. You may need to register to view the article, but registration is free.

Genetic testing is available for LCD1. Genetic Testing Registry lists the names of laboratories that are performing genetic testing for lattice corneal dystrophy. Most of the laboratories listed through Genetic Testing Registry do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional. To view more information on genetic testing for lattice corneal dystrophy type 1, click here.  

We recommend that you speak with your healthcare provider or an appropriate eye specialist regarding your concern. Your primary health care provider should be able to help you locate a eye disease specialist in your area. 

In addition, the National Eye Institute provides tips for finding an eye specialist at the following link. The NEI was created to conduct research, distribute health information, and support other programs that protect and prolong the vision of Americans.

While not an exhaustive list of specialty eye centers, you can find a list of the American Association of Eye and Ear Hospitals member facilities.