A great deal about Keratoconus is unknown and/or misunderstood. Since this disease is apparently more common than previously thought, and it has such an impact on the affected individual's vision, it is important to clarify both the condition and the available treatments.
Keratoconus is a degenerative condition that progressively thins an area of the cornea causing a bulging or "cone" shape in the thinned area. The cornea is the front clear window of the eye which focuses light onto the retina. The cornea is normally smooth and round like a dome in shape, however in Keratoconus, the cornea becomes very thin, irregular, and starts to protrude like a cone. This protruding cone shape affects the central cornea and causes the vision to become distorted.
Keratoconus is usually present in both eyes with one eye progressing faster than the other. The cause of Keratoconus is currently unknown but some factors thought to be associated with the disease are allergy and heredity. People with Keratoconus almost always seem to be "eye rubbers." It is not known whether the Keratoconus causes the intense itching or if the itching is already present causing the eye rubbing which leads to the condition. One thing is for certain, however, continued eye rubbing causes the condition to worsen significantly. It is for this reason that people with Keratoconus must not rub their eyes and are often prescribed medications to relieve the itching. Greater than one in one thousand people have the condition.
Eyeglasses may be used to treat the problem only in the early stages of the disease. Glasses will not provide good vision as the disease progresses. If the condition is not too advanced, special soft contact lenses can be used to provide vision. Rigid gas permeable contacts, however, will provide superior vision correction and are certainly the preferred treatment in moderate to severe cases. The contact lens acts as a new regular shaped clear front surface of the eye to focus light onto the retina. As Keratoconus progresses, the tip of the cone continues to thin and sometimes scars. If the cornea becomes too thin and pointed to the point that the contact lens cannot stay on the eye, a corneal transplant (called keratoplasty) is necessary. This involves removing the thinned cornea and sewing a donor cornea in its place. Most patients however, can be managed well with contact lenses and only about 10% of Keratoconus patients require a keratoplasty. It is important to note that even after a keratoplasty, special rigid gas permeable contacts are often needed to correct vision.
Contact lens fitting in Keratoconus is very different than cosmetic contact lens fitting. It can be a very time intensive and challenging procedure for both doctor and patient. Special curves on the back surface of the lens are needed to fit over the pointed area of the cone. This can require numerous office visits and lens adjustments to accomplish. Keratoconus patients have more sensitive corneas and some awareness or mild discomfort with contacts is common. First time lens wearers may require an adaptation period before comfort is attained.
Once you are fit with contacts, you will need to be monitored every six months for changes in the cone. Adjustments in your contacts will be needed as the cone continues to protrude. Failure to adhere to follow up visits can cause corneal damage. If the cone protrudes further and the contact lens is now relatively flat with respect to the new corneal shape, mechanical stresses are placed on the cornea resulting in central scarring. The scar tissue that forms in the center of the cornea can impair the vision significantly. I advise all Keratoconus patients to obtain prescription glasses for emergency back up even though vision is typically not good with glasses. Purchasing a spare set of contacts is also wise since the Keratoconus patient is so heavily dependant on their contacts for normal daily function. Should a contact get lost or broken, the Keratoconus patients may find themselves unable to do simple daily activities until a new lens is obtained. Since these contacts are very special, they sometimes can take a significant amount of time to replace.
The condition may progress to the point that contact lenses cannot provide good usable vision or that the vision is still well corrected but it has become impossible to keep a contact lens on the eye. Fortunately, with the continued advances in contact lens technology, many more people with Keratoconus are never even reaching this stage at all. Today, the historically reported rate of 10% of Keratoconus patients requiring a keratoplasty, is absolutely decreasing. However, if this point is reached despite our modern contact lens options, a keratoplasty will be indicated. After the corneal transplant is performed and the healing process is over, the individual will again be placed into special contact lenses to provide good quality vision.
The following videos are all candid comments from actual Keratoconic patients.
The following are webinars Dr. Maller did, explaining the Pentacam Corneal Scleral Profile (CSP) software, the integration with
Wave software, and ultimately the advantage to the patient to have a totally customized scleral contact lens designed uniquely
for their eye. The level of customization is contained within the many thousands of curves that are specified and the degree of
asymmetrical design that is possible which allows the lens to fit much better on the asymmetrical sclera of each patient. This
creates a more comfortable lens for the patient that also is then capable of much better performance i.e. better vision, longer
comfortable wearing times, etc.
What Is Keratoconus?
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