Keratoconus (also known as corneal ectasia) is a disease of the cornea, the clear front outer surface of the eye, that affects 1 in 500 to 1 in 2,000 people in the general population. Its cause is unknown.
Physiologically there is a breakdown of the inner tissue or layers of the cornea, called stroma or lamellae, which weakens the corneal structure and due to one’s normal eye pressure, begins to push outward creating a cone or bulge on the cornea.
The cone or bulge causes the light entering the eye to become scattered, distorting the way you see images. In advanced stages, seeing becomes extremely difficult.
Keratoconus often starts during one’s teenage years, although there have been cases reported starting both earlier in life and later. Biological changes such as puberty or pregnancy can trigger the disease.
It is most often a bi-lateral disease, meaning it affects both eyes and there can be a delay of up to five years before the second eye begins to show symptoms.
The most common symptom of keratoconus is fluctuating vision. A new set of contact lenses or glasses may provide crisp, clear vision but only for a short period of time. Within three months to one year your vision is no longer acceptable and a visit to your doctor is again required.
Our Denver eye doctor will review a topographical map of the cornea, along with other refractive measurements, which will confirm you have keratoconus.
Because of the irregular surface of the cornea, glasses and standard contact lenses only work for mild cases of keratoconus. If the disease progresses, custom made hard contact lenses, known as RGP or rigid gas permeable lens, are often used.
Due to the cornea’s irregular surface, often times contact lenses rub against the cornea due to one’s normal blinking, causing the lens to be uncomfortable after a few hours. This is referred to contact lens intolerance.
If a corneal ectasia patient is contact lens intolerant, they will be unable to wear lenses for an extended period of time and therefore they will be unable to see adequately enough to function on a daily basis.
At this point, there are two options for the patient. The first is Intacs corneal implants, a minimally invasive procedure in which a surgeon will implant two micro-thin implants made of medical plastic in the outer areas of the cornea, flattening the cone and making for a normal corneal surface. The procedure is pain free, maintenance free and can be completed within 20 to 30 minutes. Contact lenses or glasses are often worn after Intacs because the cornea has been modified to a more normalized shape.
The second option is a corneal transplant, which has been successfully performed for decades.
Visit the Addition Technoloy website for more information.
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