Keratoconus

The word keratoconus is derived from two Greek words: kerato, meaning cornea, and konos, meaning cone. Keratoconus, is a condition in which the normally round shape of the cornea is distorted and a cone-like bulge develops, resulting in significant visual impairment. This corneal change usually begins in the late teens or early twenties and progresses over time. As the keratoconus progresses, the cornea bulges and thins, becoming irregular and sometimes forming scars. The end result of this progression can range from a minimal visual disturbance that can be corrected with glasses or contact lenses to a severe corneal change that necessitates a cornea transplant to improve vision.

 

 

What causes Keratoconus?

Keratocunus has been estimated to occur in one out of every 2,000 persons in the general population. Recent research has yet to fully uncover the cause of keratoconus, however, several theories exist. A few links have been observed:

1) Inherited
2) Linked to other medical conditions such as Down’s syndrome and Atopic Skin Disease
3) Constant eye rubbing)
4) No link at all (the large majority of patients have no family history or other eye condition)

 

Signs and Symptoms
The first symptom of keratoconus noted by the patient is a blurring and distortion of vision that can be corrected with glasses. Often times the spectacles require frequent changes, as the disease progresses. The continued thinning of the cornea usually progresses slowly for five to 10 years and then tends to stop. Occasionally, it is rapidly progressive and, in the advanced stage, the patient may experience a sudden clouding of vision in one eye that clears over a period of weeks or months. This is called "acute hydrops" and is due to the sudden infusion of fluid into the stretched cornea. In advanced cases, superficial scars form at the apex of the corneal bulge resulting in more vision impairment.

 

How is Keratoconus Treated?
In the mildest cases of keratoconus, ordinary eyeglasses may correct the near-sightedness and astigmatism caused by this corneal change. More advanced forms of keratoconus require gas permeable contact lenses which must be specially fitted by someone specially trained to do this. In about 15% of patients, the abnormal curvature is unable to be corrected by glasses or contact lenses, requiring a surgical procedure. New advances in surgical procedures have allowed for excellent outcomes in keratoconus patients requiring surgery. Three surgical options are available and are briefly described below.

1) INTACS® - Prescription inserts for milder keratoconic patients that help correct the abnormal curvature. In some cases, INTACS can delay or eliminate the need for a corneal transplant.

2) Corneal Transplant – This procedure replaces the patients cornea with a donor cornea. Traditionally the entire cornea of the patient is replaced (called a Penetrating Keratoplasty, PK), however new surgical technques require only the diseased portion of the patients cornea to be replaced. This surgery (called a Deep Anterior Lamellar Keratoplasty, DALK) allows for a significantly quicker recovery time along with a significant decrease in graft rejection.