Keratoconus is a non-inflammatory ectasia or protrusion of the cornea. It is characterized by progressive thinning and steepening of the central cornea. As the cornea steepens and thins, the patient experiences a decrease in vision which can be mild or severe depending on the amount of corneal tissue affected. The onset of keratoconus usually starts in the teenage years or early 20s. It rarely develops after the age of 35. Keratoconus shows no gender predilection and is bilateral in over 90% of cases. In general, the disease develops asymmetrically. Diagnosis of the disease in the second eye usually lags 6 or 7 years after diagnosis in the first. The incidence of keratoconus is about 2 to 3 people per 1000 population.
As the condition progresses, the distorted cornea will require a contact lens, usually rigid gas permeable. The progression of keratoconus is unpredictable. While keratoconus interferes with the clarity of a persons sight, it rarely causes blindness. With the latest contact lenses specifically designed for keratoconus, the need for a corneal transplant is extremely remote. Recently, several soft lens have been introduced for the treatment of keratoconus, including the Soft K lens and the Flex lens.
What Causes Keratoconus?
The characteristics of keratoconus have been known for at least 200 years, but the specific causes are still undetermined. Several theories have been proposed. One theory is that keratoconus is genetic in origin. About 7% of patients have other family members with the disease. Another view holds that keratoconus is secondary to some disease process. While there are many theories, research into keratoconus continues.
Keratoconus TreatmentHow is Keratoconus treated?
As keratoconus advances, rigid gas permeable lenses are the first choice to correct vision adequately. Most of the time this is a permanent remedy. Because of the progression of the disease, it is important that the lenses are fitted with great care and are reassessed at least annually by eye care professionals. The lenses that we use have a complex geometry that takes into account the conical shape of the cornea for all stages of the condition. The lenses have multiple curves which are custom designed to fit each individual cone correctly without traumatizing the delicate compromised corneal tissue. For almost all patients, this means better comfort and optimum visual acuity. Additional features of these newest of keratoconus lens designs include:
2. They are easy to insert, remove and clean.
3. They provide excellent health to the eye, because they allow the cornea to “breathe” oxygen directly through the lens.
4. The central zone of the lens fits directly over the cone. Consequently, the lens will not slide around on the cornea causing ocular irritation or scarring. The concept of this unique fit is similar to the manner in which a bra is fitted over a breast.
Why is it that I always have pain in my eyes and the sunlight “kills” me?
The lenses that you are wearing are probably not fit correctly. We see this often when the lenses are fit too flat, and the design of the lens is not appropriate. The lenses are moving excessively over the cornea with each blink causing abrasions to the apex of the cone. If this continues, irreversible scarring will result and visual acuity will diminish. When I get to see a cornea like this, I often have to refit with a new rigid lens over a special soft lens which acts as a bandage. The soft lens allows the cornea to heal, while the rigid lens provides vision. Typically, this “piggy back” combination lasts no more than a few weeks. As the cornea heals, new measurements of the corneal curves are taken. It is not unusual to encounter changes in the curves and contour of the healed cornea. As this takes place, new rigid lenses are ordered to fit the healed cornea.