Keratoconus is an eye condition in which the cornea - the window of the eye - progressively thins affecting the ability of the eye to properly focus. The cornea is normally dome-shaped - Keratoconus causes it to have a cone-like bulge. The condition can eventually cause poor vision.
What are the causes of Keratoconus?
There are many possible causes of Keratoconus. It may be caused by hereditary factors - approximately one in ten patients have a parent with the same condition. It is most common in non-caucasian patients and generally affects about one in 450 of the population. However, environmental factors are also believed to play a role, such as an injury to the eye, diseases such as retinitis pigmentosa and atopic allergies which cause the patient to vigorously rub their eyes. Many experts also believe that the endocrine system is also linked to the condition as Keratoconus is usually first detected during puberty and progresses during pregnancy. However, this is a controversial theory that has not yet been proven.
What are the types of Keratoconus?
There are many different types of Keratoconus which are determined by the location and shape of the thinned cornea. The main types are:
This is the mildest form of the condition and is usually symptom-free. It is usually only diagnosed via corneal topography. Forme Fruste is very common and no treatment is generally required other than glasses or soft contact lenses.
The shape of the corneal bulging will affect the quality of the patient's vision as it is very near the pupil. Depending on the severity of the symptoms, treatment options will include speciality small diameter hard contact lenses, hybrid contact lenses, or scleral contact lenses.
This is by far the most common form of cerataconus. The area of bulging is notably larger and is usually observed inferior and temporally on the cornea. General observation often reveals a sagging appearance to the cornea.
Although the area of bulging and thinning is located further down the cornea, the corneal distortion does extend into the central part of the cornea. This means that vision will be significantly decreased with glasses and soft contact lenses.
Oval cone Keratoconus is best corrected with the use of scleral contact lenses or a Hybrid Contact Lens in some circumstances.
This is defined as expansive corneal thinning and bulging affecting over 75 percent of the cornea. It is the most severe form of cerataconus but is also the rarest. Globus Cone is the most likely type of Keratoconus to need a corneal transplant known as a Penetrating Keratoplasty (PKP).
The extensive area of thinning means that this type of Keratoconus is usually only correctable with a large diameter Scleral Contact Lens.
What are the symptoms of Keratoconus?
Keratoconus usually affects both eyes and the symptoms can vary considerably, and change over time.
In the early stages, common symptoms are:
- 1. eye redness or swelling
- 2. blurring of vision
- 3. vision that is slightly distorted so that straight lines, for example, look bent or wavy
- 4. increased sensitivity to light and glare
As the disease progresses, symptoms frequently include:
- 1. vision that is increasingly blurry and distorted
- 2. Increased nearsightedness or astigmatism. More frequent prescriptions may be necessary
- 3. Being unable to wear contact lenses as they may no longer fit properly and feel uncomfortable
How can you prevent Keratoconus?
As Keratoconus is largely a genetic condition, it is not possible to prevent the condition from developing. However, if you have been diagnosed with Keratoconus, it is certainly possible to take steps to prevent the condition from worsening. The most important thing is to refrain from rubbing your eyes as this has been shown to aggravate symptoms. Always follow the advice of your optician who will prescribe you with the correct treatment to alleviate your symptoms. Lifelong eye examinations are highly recommended. For more advice about the diagnosis and management of Keratoconus, contact the Orbit Eye Hospital for the latest treatments and up-to-date advice.