Keratoconus - Causes, Symptoms, Diagnosis & Treatment

Keratoconus : The Disorder Of The Cornea

Dr.Nitesh Narayen profile Authored by Dr.Nitesh Narayen on 25 Aug 2014 - 14:30.

Keratoconus or KC is a non-inflammatory eye condition in which the normally round dome-shaped cornea progressively thins causing a cone-like bulge to develop. This results in significant visual impairment to the patient over a period of time.

 

 

 

 

Tiny fibers of protein in the eye called collagen help hold the cornea in place and keep it from bulging. When these fibers become weak, they cannot hold the shape and the cornea becomes progressively more cone shaped. Keratoconus appears to run in families. If you have it and have children, it’s a good idea to have their eyes checked for it, starting at the age of ten.

The early stages of Keratoconus cause slight blurring and distortion of vision and increased sensitivity to glare and light. These symptoms usually first appear in the late teens and early twenties. Keratoconus may progress till about 30 years of age and then slow or stabilize. It affects each eye differently.

To make sure you have Keratoconus, your doctor needs to measure the curvature of the cornea. There are several different ways this can be done:

One instrument, called a keratometer, shines a pattern of light onto the cornea. The shape of the reflection tells the doctor how the eye is curved. There are also computerized instruments that make three-dimensional "maps" of the cornea.

The estimates of the prevalence for Keratoconus range from 1 in 500 to 1 in 2000 people, but difficulties with differential diagnosis cause uncertainty about its prevalence. It seems to occur in populations throughout the world, although it is observed more frequently in certain ethnic groups, such as South Asians. Environmental and genetic factors are considered possible causes, but the exact cause is uncertain. It has been associated with detrimental enzyme activity within the cornea, and is more common in patients with Down syndrome.

The mild nearsightedness and astigmatism caused in the early stages of keratoconus can be corrected with eyeglasses or soft contact lenses. Rigid gas permeable contact lenses are generally prescribed to correct vision more adequately with the cornea continuing to thin and change shape.

In patients who are intolerant to contact lenses and not comfortable with glasses we can implant INTACS in the cornea which corrects irregular astigmatism and improves the quality of vision. Dr. NiteshNarayen was the first corneal surgeon in AP to use femtosecond laser to create channels for their implantation. In severe cases, a corneal transplant may be needed due to scarring, extreme thinning or contact lens intolerance. This is a surgical procedure that replaces the Keratoconus cornea with healthy donor tissue.

Are there any latest technologies that can better the treatment for Keratoconus?

Corneal crosslinking, often called CXL for short, strengthens corneal tissue to halt bulging of the eye's surface in Keratoconus. With epithelium-off crosslinking, the outer portion of the cornea (epithelium) is removed to allow entry of riboflavin, a type of B vitamin, into the cornea, which then is activated with UV light. With the epithelium-on method (also called transepithelial crosslinking), the corneal surface is left intact.

This epithelium-on method requires more time for the riboflavin to penetrate into the cornea, but advantages include less risk of infection, less discomfort and faster visual recovery, according to proponents of this technique. Corneal crosslinking may reduce significantly the need for corneal transplants among Keratoconus patients.

Dr. Nitesh Narayen had presented a paper in ESCRS 2013, Amsterdam citing that patients younger than 18 years who had undergone C3R had visual improvement as well. It also is being investigated as a way to treat or prevent complications following LASIK or other vision correction surgery. Using a combination of corneal crosslinking and Intacs implants (see above) also has demonstrated promising results for treating keratoconus.

Topography-guided conductive keratoplasty: While more study is needed, early results of a small study involving topography-guided Conductive Keratoplasty (CK) show this procedure might help smooth irregularities in the corneal surface. This treatment uses energy from radio waves, applied with a small probe at several points in the periphery of the cornea to reshape the eye's front surface. A topographic "map" created by computer imaging of the eye's surface helps create individualized treatment plans.

Deep Anterior Lamellar Keratoplasty (DALK): With advancement in corneal surgical techniques, it is now possible to selectively remove the anterior layers from the cornea and replace it with donor tissue to restore its anatomy and function. DALK is one such procedure wherein the host corneal endothelium is retained, and anterior corneal tissue is replaced with normal thickness donor tissue. As the host endothelium is retained there is no risk of rejection, and steroids have to be given only for a short duration of time. However, DALK surgery requires more surgical expertise compared to the traditional full thickness keratoplasty, and hence performed by only well trained corneal surgeons all over the world.

In its initial stages, Keratoconus causes slight blurring and distortion of vision and increased sensitivity to light. These symptoms usually appear in the late teens and early twenties. It may progress for 10-20 years and then stabilize. Each eye may be affected differently.

What can be done about Keratoconus treatment?

In the early stages, eyeglasses or soft contact lenses may be used to correct the mild nearsightedness and astigmatism caused in the initial stages of Keratoconus. As the disorder progresses and the cornea continues to thin and change shape, rigid gas permeable (RGP) contact lenses are generally prescribed to correct vision more adequately. The contact lenses must be carefully fitted, and frequent checkups and lens changes may be needed to achieve and maintain good vision. Intacs, intracorneal rings, are sometimes used to improve contact lens fit.

Corneal crosslinking is a new treatment option under investigation to halt the progression of keratoconus.

A corneal transplant may be needed in severe cases due to scarring, extreme thinning or contact lens intolerance. This is a surgical procedure that replaces the Keratoconus cornea with healthy donor tissue.

Eyeglasses or soft contact lenses may be used to correct the mild nearsightedness and astigmatism caused in the early stages of keratoconus. As the disorder progresses and the cornea continues to thin and change shape, rigid gas permeable contact lenses are generally prescribed to correct vision more adequately. The contact lenses must be carefully fitted, and frequent checkups and lens changes may be needed to achieve and maintain good vision.

In severe cases, a corneal transplant may be needed due to scarring, extreme thinning or contact lens intolerance. This is a surgical procedure that replaces the keratoconus cornea with healthy donor tissue.

 

 

 

 

*Disclaimer This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.