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Corneal dystrophies

Your cornea is the clear part of the front of the eye. Corneal dystrophies are common genetic conditions which cause changes to your cornea without any inflammation, infection or other eye disease.

Corneal dystrophies affect the clearness of your cornea and usually involve both eyes. Although they can often get worse over time, normally this happens very slowly. Many corneal dystrophies develop so slowly that they may never get to a point where they affect your vision.


Corneal dystrophies can often run in families, but may not always do so. In some cases, it may not be possible to say why someone has developed their corneal dystrophy.

Types of corneal dystrophies

The cornea is made up of layers. Each layer has a different role in keeping the cornea healthy and clear. Corneal dystrophies are often classified by layers of the cornea they affect.

  1. Epithelial dystrophies: The epithelium is the thin outermost layer of the cornea. A common symptom of an epithelial dystrophy is a painful ‘foreign body’ sensation, which can feel like there is something in your eye. The epithelium can heal quickly so you may not experience these symptoms for very long. Treatment can be given to relieve your symptoms and aid healing.
  2. Stromal dystrophies: The stroma is the middle layer of the cornea. Stromal dystrophies cause deposits to build up in this layer. These deposits make your stroma less clear, affecting vision. Changes in your stroma can also affect other layers of your cornea.
  3. Endothelial dystrophies: The endothelium is an extremely thin single layer of cells, which makes up the innermost layer of your cornea. This layer is vital for keeping the cornea clear, as it acts as a pump controlling the movement of fluids and nutrients in and out of your cornea. Without this pump, the cornea can swell with fluid, causing your vision to become hazy.

Corneal blindness is one of the major causes of visual deficiency after cataract, glaucoma and age-related macular degeneration (AMD). Trachoma is responsible for nearly 4.9 million blind people and it mainly is a result of corneal scarring and vascularization. Ocular trauma and corneal ulcerations are significant causes of corneal blindness. Traditional eye medicines have also been implicated as a major risk factor in the current epidemic of corneal ulceration in developing countries.

The only currently available curative treatment is surgery, by graft of cornea. Due to the lack of donors, the access to this surgery is very difficult, even in developed countries. WHO recommends that public health prevention programmes as the most cost-effective means of decreasing the global burden of corneal blindness.