Keratoconusor conical cornea, as it is sometimes called, is a rare condition primarily affecting teenagers and people in their early 20’s. It is characterized by a thinning of the cornea, and an irregular surface of the cornea, which causes a cone shaped appearance, distortion of the visual image, and reduced vision. It is this irregular distortion of the cornea that makes it difficult for glasses to fully correct vision.
Bowing of the cornea causes a cone shaped appearance.
Signs and symptoms: Poor vision that cannot be corrected fully with glasses may indicate a condition of Keratoconus. Many patients are initially unaware that they have this condition, and have to continue seeing their eye doctor for prescription changes to their glasses. The list of signs and symptoms mentioned in various sources for Keratoconus, include the 7 symptoms listed below:
- Blurred vision
- Astigmatism
- Myopia
- Both eyes affected
- Light sensitivity
- Distorted vision
- Nearsightedness
Cause: The cause for Keratoconus is unknown. It is more common with people who wear contact lens, and people who are nearsighted. There is some speculation that excessive rubbing of the eye due to allergy may play a role. Keratoconus can be associated with certain other eye diseases, and other medical conditions. Only 13-15% of these patients have a family history of Keratoconus.
Diagnosis: Keratoconus is most often diagnosedby a cornea specialist. In the early stages of the disease there may be no obvious finding, and the diagnosis is only made by computerized videokeratography.
Common
Treatments:
While visual acuity is decreased, it can generally be corrected to 20/20 with gas-permeable contact lenses, but the vast majority of patients often see best with rigid contact lenses since these lenses provide a clear surface in front of the cornea, allowing the light rays to be projected clearly to the retina.
Prognosis:
The progression of Keratoconus usually slows down at puberty and may progress to the mid thirties when progression often stops. Any time between the ages of 12 and 35, it can begin or arrest. It is not possible to make predictions on the pace of the progression, or if it will progress at all. Young patients with advanced Keratoconus are more likely to need some form of surgical intervention in the future. Keratoconus may occur in one eye but commonly affects both eyes, with one eye being more affected than the other. Both males and females are equally affected.
Surgical Treatments:
As Keratoconus progresses, scarring of the cornea can occur, causing it to become deformed and unable to obtain an adequate fit with contact lenses.
CORNEAL REPLACEMENTmay be necessary to surgically replace the cornea with a cornea of more regular shape enabling the patient to again wear contact lenses if necessary. Prognosis is generally good for most people.
Newer procedures:
HIGH FREQUENCY RADIO ENERGY that shrinks the edges of the cornea, pulling the central area of the cornea back to a more normal shape. This can help delay or avoid the need for a corneal transplantation.
INTACS - a technique which involves flattening the cornea with the insertion of two arc like plastic segments into the middle of the cornea, making it more able for thepatient to wear contact lenses.
References:
Cornea Genetic Eye Institute. (2009). Welcome to the KeratoconusCenter.
Retrieved June 30, 2010, from
Keratoconus. (30 June, 2010). Retrieved June 30, 2010, from
Keratoconus. (n.d.). Retrieved June 30, 2010, from
The Eye and Keratoconus. (n.d.). Retrieved June 30, 2010, from
National Keratoconus Foundation. (1998 - 2010).
How The Eye Works. Retrieved June 30, 2010, from
MedlinePlus. (n.d.). Keratoconus. Retrieved June 30, 2010, from
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