Corneal Dystrophies
Corneal dystrophies are a series of disorders or diseases that occur in different parts of the cornea. Depending on the individual and specific condition these diseases may or may not have apparent symptoms, while they may also have significant visual impairment. Unlike many diseases of the eye that are age related, corneal disease may occur at any age. With the exception of Fuchs Dystrophy, which affects more women than men, the incidence of corneal disease is generally the same for men and women. Since many corneal dystrophies appear to have a genetic component, the conditions tend to affect both eyes, develop relatively slowly and are limited to affecting the eyes.
A standardized classification of the corneal dystrophies, approximately 20 defined conditions, has been developed. The classification of the disease takes into account the chromosomal loci of the dystrophies as well as the responsible genes and their mutations. Traditionally, these disorders are classified based upon their clinical findings and the specific layer of the cornea affected. As our knowledge of genetics advances there may be a greater understanding of the disease leading to more advanced treatment options.
Symptoms
Corneal dystrophies are characterized by the accumulation of foreign material or excess water in one or more of the five layers of the cornea. The excess material leads to a loss of corneal transparency, which then creates blurry or compromised vision. A related symptom common to some forms of corneal dystrophy is chronic corneal erosion which occurs when the thin outer layer of the cornea (epithelium) does not bind properly to the eye. The symptoms of recurrent corneal erosion are discomfort or severe pain, abnormal sensitivity to light (photophobia), foreign body sensation, and blurred vision.
Diagnosis
Due to the asymptomatic nature of many of the corneal dystrophies the diagnosis may be determined incidentally during a routine eye examination. Patients may complain of unspecified decrease of visual acuity or blurriness. Standardized eye examination techniques utilizing a slit lamp (a special microscope that projects a line of light onto the eye surface that is viewed through a microscope). In certain cases where there is a family history the patient may be given a genetic test before symptoms are present.
Treatment
Treatment of corneal dystrophies varies significantly. In the case of individuals who do not have symptoms (asymptomatic) or mild symptoms the approach may be to regularly observe to monitor the progression of the disease with no specific treatment initially prescribed.
In patients with progressive disease with more serious symptoms the treatment may include eye drops, ointments, lasers, surgical cell transplantation, or a corneal transplant. Recurrent corneal erosions (a common finding in most corneal dystrophies) may be treated with lubricating eye drops, ointments, antibiotics or specialized contact lenses. When recurrent erosions persist, additional treatments such as corneal scraping or the use of excimer laser therapy may be used to remove surface abnormalities from the cornea.
In cases where there are significant symptoms a corneal transplant, known as a keratoplasty, may be necessary. Corneal transplants have been highly successful in treating individuals with advanced symptoms of corneal dystrophies. While the success rate for corneal transplants is quite good, there is a risk that in certain corneal dystrophies the lesions will eventually develop in the transplanted cornea.
Please Note: The information on corneal dystrophies provided in this section is general in nature and is for educational purposes only. The information should not be used for diagnostic or treatment purposes. If you have or suspect you have any medical condition you should immediately seek the advice of an ophthalmologist, general practitioner, optometrist, or other medical professional.