What is it?
Corneal dystrophy is a hereditary genetic disease that affects the cornea, the circular transparent wall in the anterior part of the eye. It usually affects the central part of the cornea of both eyes without causing eye inflammation in patients between the age of 10 and 40 and progresses slowly.
Causes and risk factors
A mutation of chromosones is the cause of this disease, which is why, the presence of this disease in a family, specially in a patient's close family, is a risk factor. This mutation leads to an accumulation of materials or substances that should not be in the cornea. This disease has not been associated with environmental factors or other systemic diseases.
The types of corneal dystrophy are classied according to the layer of the cornea that is affected:
- Meesmann epithelial corneal dystrophy and Cogan fingerprint lines, geographic map-like lines and dots are dystrophies that affect the epithelial layer, the most superficial layer of the cornea. Reis-Bücklers corneal dystrophy and Thiel-Behnke corneal dystrophy affect the the Bowman's membrane, between the epithelium and the most profound layers.
- Stromal dystrophies affect the stroma of the cornea, the thickest layer. The most common are corneal dystrophy Groenouw type I, macular dystrophy Groenouw type II and reticular distrophy, etc.
- The endothelial distrophies and the Descemet's membrane are changes to the most profound layers. Fuchs endothelial corneal dystrophy is one of the most common.
The symptoms of patients with corneal dystrophy are very varied. Many do not have any symptoms, especially at the start of the disease. Patients whose most superficial layers are affected usually develop epithelial recurrent erosion leading to irritation and eye ache in the morning which comes and goes.
However, patients with stromal dystrophy usually have reduced visual acuity because of deposits of anomalous substances in the central area of the cornea. A loss of vision is also the main symptom in patients with endothelial dystrophies.
However, in this group of patients, reduced vision is due to the poor functioning of endothelial cells whose role is to prevent excess liquid in the cornea and thus, maintain its transparency. As a result of the cellular change in this layer, the excess liquid penetrates the cornea causing a corneal oedema (swollen cornea due to liquid retention) leading to its loss of transparency and a reduction of visual acuity.
At present, there is no effective means of preventing this disease. In the future, genetic engineering may be a useful tool for changing and standardising the mutated chromosones that cause this disease.
Treatment for corneal dystrophy depends on its type, the symptoms of the patient and its severity.
Patients who are symptomless do not require treatment.
Patients with recuring erosions are treated with lubricating eyedrops and ointments, therapeutic contact lenses or a PTK excimer laser depending on the severity of the eroision and the response to each treatment.
Patients with a significant loss of vision due to deposits of materials or anomalous substances in the stroma require a cornea transplant, be it a full cornea transplant (penetrating keratoplasty) or just the most anterior layers (deep lamellar keratoplasty) con pérdida de visión importante debido a depósitos de materiales o sustancias anómalas en el estroma requieren un trasplante de córnea, sea un trasplante de grosor total (queratoplastia penetrante) o de solo de las capas más anteriores
En pacientes con acúmulo de líquido en la córnea por mal funcionamiento de las células endoteliales, el tratamiento consiste en colirios y pomadas hiperosmolares en las fases tempranas de la enfermedad. Si la disminución de la agudeza visual progresa y limita las actividades diarias del paciente, la opción sería el trasplante de córnea, ya sea un trasplante de grosor total o trasplante solo de las células endoteliales (queratoplastia posterior).
Professionals who treat this pathology
Frequently asked questions
Once corneal dystrophy has been diagnosed, what can be done to slow the onset of the disease?
Due to the fact that the disease is genetic and environmental influences and dietary factors do not have any affect on it, nothing can be done to stop it from progressing or make it progress more slowly. No indicators have been identified to reveal the prognosis of each patient, that is to say, there's no way of knowing in advance which patients will progress more quickly or slowly or who will need surgical treatment.
After a cornea transplant, could the disease affect the cornea once again?
In general, the condition may affect the new transplanted cornea although the incidence rate is different for each kind of dystrophy. For example, in lattice stromal dystrophy and granular stromal dystrophy, there are cases where the transplanted cornea once again has anomalous deposits leading to a second transplant. However, in macular stromal dystrophy, it is rare for this to happen.