Corneal Dystrophies
Corneal dystrophy is a group of disorders, characterised by a noninflammatory, inherited, bilateral opacity of the transparent front part of the eye called the cornea. Fuchs’ dystrophy is an inherited condition that affects the delicate inner layer (endothelium) of the cornea. The endothelium functions as a pump mechanism, constantly removing fluids from the cornea to maintain its clarity. Patients gradually lose these endothelial cells as the dystrophy progresses. Once lost, the endothelial cells do not grow back, but instead spread out to the fill empty spaces. The pump system becomes less efficient, causing corneal clouding, swelling and eventually, reduced vision.
Corneal dystrophy may not significantly affect vision in the early stages. However, it does not require proper evaluation and treatment for restoration of optimal vision. It can, however, rarely cause corneal ulceration, especially with epithelial dystrophy. It appears as grayish white lines, circles, or clouding of the cornea. Corneal dystrophy can also have a crystalline appearance.
Treatment:
To treat for endothelial cell dystrophy, steps are taken to remove moisture from the eyes, using different ointments and eye drops. But these measures often fail to stop the
progression of the condition, so a corneal transplant may be needed, using tissue taken from the eyes of a donor. Tissue matching to prevent rejection of the transplanted tissue is not as important for a corneal transplant as for other organs. Because the cornea has very few blood vessels, it is less exposed to attack by the immune system. Corneal transplants were thus the first to be widely successful in human patients. A network of eye banks exists to obtain corneal tissue and match it for appropriate patients.
Inheriting Corneal Dystrophy
There are two methods by which corneal dystrophies can be inherited. The first is called ‘autosomal dominant’ and the second ‘autosomal recessive’. The ‘dominant’ method means that one of the parents actually has the condition. Each time that parent has a child, there is a 50 per cent (one in two) chance of the child having the condition as well. The ‘recessive’ method is slightly more complicated. Neither of the parents actually has the condition themselves but they will both be ‘carriers’ of the condition. If two ‘carriers’ have children, there is a 25 per cent (one in four) chance that each child will have the condition.
Sources:
1. http://www.molvis.org/molvis/v13/a198/yellore-fig1.html
2. http://www.stlukeseye.com/Conditions/Fuchs.asp
3. http://en.wikipedia.org/wiki/Corneal_dystrophy
4. http://www.visionrx.com/library/enc/enc_corndyst.asp#treatment
5. http://www.corneatransplant.cornealdystrophy.com/
developed by: Darren Stilwell