Keratoconus is a disease in which the cornea of the patient thins and gradually bulges out taking the shape of a cone. Name of this disease keratoconus was formed by joining two Greek words Kerato meaning cornea and konos meaning cone. Keratoconus produces blurred vision and sensitivity to light. Keratoconus usually occurs in patients in the age group of 10 to 25 and usually occurs in both their eyes. In the earlier stages of this disease, problems of vision caused by Keratoconus can be managed by wearing power glasses or soft contact lenses. As the disease increases rigid glasses with higher powers may be needed and at the end cornea transplant will be necessitated to find permanent solution to this problem.
Symptoms of keratoconus changes as the disease progresses slowly. Some of them are given below.
- Distorted or blurred vision
- Increased sensitivity to light
- Night vision problems
- Needs to change eye glasses continuously
- Cornea ruptures and the eye are filled with a fluid (hydrops)
Causes for the formation of keratoconus are not known to medical science. It is generally found to happen in families. If an elder person has keratoconus it is better that he may test his children for this disease as this disease is found to start in children from the age of 10. Usual causes are detailed below.
- Continuous rubbing of eyes.
- Eye conditions like retinopathy, retinitis pigmentosa etc can be a reason in the formation of keratoconus.
- Combination of other disorders like enzyme abnormalities, hereditary factors like down syndrome etc can also cause this disease.
- Wearing of contact lenses for several years.
Doctor will be able to make an initial diagnosis based on your medical history, symptoms and a routine examination. Other diagnostic tests that he may suggest include:
Eye Refraction : Your doctor may use a device with different wheels for different lenses or other devices to study how light is projected and refracted by your eye.
Slit-lamp Examination : With this device your doctor will evaluate the shape of your cornea. This test will be repeated after applying eye drops to dilate the retina.
Keratometry : In this test a circle of light is focused on the cornea and by measuring the reflection, the curve of your retina is assessed by your doctor.
Computerized Corneal Mapping : With the help of scanning techniques such as corneal topography, coherence topography etc images of cornea is obtained, which can be made used for measuring the thickness of the cornea.
Treatment options for cornea depend upon the severity of the disease. After a few years the affected cornea becomes stable and much vision problem is not felt by the patients of keratoconus.
Contact Lenses and Eye Glasses : For moderate keratoconus use of eye glasses or contact lenses as suggested by the physician will be enough to solve the problem. But usually the prescription for contact glasses needs to be changed frequently as the cornea bulges further and further.
Rigid Contact Lenses : As the bulging of the cornea increases, usually rigid contact lenses which are gas permeable are used. This may be inconvenient at first, but usually the patients get accustomed and do not feel much discomfort. If this is uncomfortable, your doctor may suggest a hard rigid glass on a soft base. This is known as piggybacking. Finding a lens suitable to the patient is a very important aspect and it is so very important that you select an experienced doctor who is very familiar with this technique.
Hybrid Contact Lenses : Hybrid contact lenses are lenses with rigid center surrounded by softer outer cover. This type of contact lenses is suitable for persons who cannot tolerate harder contact lenses.
Scleral Contact Lenses : This type of lens is used for patients in the advanced stages of keratoconus who have irregular changes in the cornea. This type of contact lenses sits on the white portion of the eye known as sclera and passes above the cornea without touching it.
When the cornea is very thin and there are scars on it, use of contact lenses or other type of glasses will not be of any use. In such cases surgical procedure will have to be resorted to, for finding a solution to the problems caused by keratoconus. Different type of surgical procedures is followed by surgeon for the removal of keratoconus. The most important of them are explained below.
Conreal Inserts : In this surgery crescent shaped plastic material is inserted into the cornea for providing support to it. This insertion helps the cornea to regain its shape. Furthermore, this surgery also helps the fitment of contact lenses. As the corneal inserts can be removed when needed, this surgery can be considered as a temporary measure only.
Cornea Transplant : If the patient???s cornea is extremely thin or there are sever scars on the cornea, then transplanting the cornea is the only solution left.
Lamellar Keratoplasty : Lamellar keratoplasty is a procedure in which only the anterior portion of the cornea is removed and substituted by a donor tissue.
Penetrating Keratoplasty : Penetrating keratoplasty is another procedure in which a full cornea is transplanted. In this procedure the entire cornea is removed and donor tissues are transplanted there.
Deep Anterior Keratoplasty : In Deep anterior keratoplasty inner layer of the cornea is preserved. This reduces the possibility of rejection that may happen in a full thickness replacement.