Corneal Dystrophy

Corneal dystrophy is defined as a collection of rare hereditary non-inflammatory disorders of the cornea. Corneal dystrophy occurs because of an unusual build-up of substances on the cornea of the eyes. All these disorders exhibit characteristics that resemble each other like they all affect both the eyes (i.e. they occur bilaterally), they develop slowly and do not affect any other part of the body. The cornea is the outermost transparent layer of the eye, and it consists of five layers. The dystrophy could be caused due to deposition of foreign materials in any one of these layers of the cornea.

Corneal dystrophy is a genetic disease, and hence, these disorders are inherited within the families and develop slowly. To understand the layers of the cornea, let us take a quick look at the five different layers:

1. The outermost layer protecting the eye is called the epithelium.
2. The second layer after the epithelium layer is called the Bowman’s membrane.
3. Next comes the thickest and most flexible layer of the cornea, which is made up of water, collagen fibres, and other connective tissue called the stroma.
4. The fourth layer is a strong and thin protective layer called Descemet’s membrane. 
5. The final and innermost layer of the cornea is the endothelium, and it is responsible for pumping out the excess water off the cornea.

Corneal dystrophy being a genetic disorder is caused due:

1. Inheritance of the dominant genetic disorder from either one of the parents
2. Inheritance of recessive genetic disorder from both the parents

Risk Factors

1. The primary risk factor for corneal dystrophy is the family history of corneal dystrophy.
2. Generally, the disorders affect men and women equally, except the Fuchs’ dystrophy, which is prevalent in women.

As there are many different types of corneal dystrophies, the symptoms depend on the type of corneal dystrophy. The symptoms of corneal dystrophy vary from person to person. Some of them may not exhibit any symptoms at all. The symptoms of corneal dystrophy in general are:

1. Blurry vision
2. Loss of vision
3. Corneal erosion leading to:
   1. Sensitivity to light
   2. A sensation of an unknown object in the eye
   3. Mild to severe eye pain

The corneal dystrophies are diagnosed in the following ways:

1. The ophthalmologist (eye doctor) will look into your eyes using a slit lamp microscope, which will shine a bright sheet of light into the front part of your eyes to examine your eyes thoroughly.
2. The ophthalmologist will inquire about your family medical history of eye diseases.
3. If you have a family history of eye diseases, your ophthalmologist may suggest genetic testing in some cases.

In general, corneal dystrophies are diagnosed during routine eye examinations.

Various corneal dystrophies are treated using different types of treatments. The two significant factors that decide the type of treatment are:

1. The form of dystrophy
2. The severity of the condition

The various treatments prescribed for people with corneal dystrophy are as follows:

1. Corneal erosion is one of the major concerns of corneal dystrophy that may be treated by: 
   1. Ointments
   2. Eye drops to lubricate the eyes
   3. Antibiotics 
   4. Special protective soft contact lenses for cornea
2. In cases where erosion cannot be controlled, the treatment options may include:
   1. Laser therapy
   2. Scraping techniques for scrapping the cornea
3. Severe conditions of corneal dystrophy may warrant treatment methods like:
   1. Corneal transplantation (keratoplasty), where the damaged or diseased corneal tissue is replaced by clear donor corneal tissue
   2. In cases of Fuchs’ dystrophy, where there is endothelial dystrophy, the disorder is treated by partial cornea transplant (endothelial keratoplasty)

If not treated on time, the significant risk is the potential loss of vision, requiring a corneal transplant. The following symptoms might be noticed:

1. Severe pain 
2. Very reduced vision leading to blindness