Keratoconus

What Is Keratoconus Eye Disease?

Keratoconus, often referred to as ‘KC’, is a non-inflammatory eye condition in which the typically round dome-shaped cornea progressively thins and weakens, causing the development of a cone-like bulge and optical irregularity of the cornea. This causes ‘static’ in your vision and can result in significant visual impairment.

What Causes Keratoconus?

Keratoconus is thought to be hereditary. New research is leaning toward a correlation between allergy sufferers and eye rubbing. Allergy sufferers who frequently “knuckle-rub” their eyes are more susceptible to developing keratoconus.

What are the Symptoms of Keratoconus?

Keratoconus typically first appears in individuals who are in their late teens or early twenties, and may progress for 10-20 years, and then slow or stabilize. Each eye may be affected differently. In the early stages of keratoconus, people might experience:

• Slight blurring of vision
• Distortion of vision
• Increased sensitivity to light

The cornea is responsible for focusing most of the light that comes into the eye. Therefore, abnormalities of the cornea, such as keratoconus, can have a major impact on how an individual sees the world, making simple tasks such as driving a car or reading a book very difficult.¹

How Does Keratoconus Affect Vision?

• It can result in significant vision loss; and
• May lead to corneal transplant in severe cases

You can find more information from the National Keratoconus Foundation at www.NKCF.org

Keratoconus Diagnosis

Early keratoconus is most easily diagnosed thru corneal topography, which is essentially a mapping of the corneal surface. Later stages can be diagnosed during a slit lamp exam, where the conical shape is readily apparent.

Keratoconus Treatment

Keratoconus causes blurred vision and distortion, and in its early stages can be treated with glasses, custom soft contact lenses, or rigid gas permeable lenses.

As the disease progresses surgical intervention is required.

Current surgical options include INTACS and corneal transplants.

• INTACS are surgically implanted corneal inserts that are placed peripherally, outside the central optical zone, to reshape the cornea and correct the nearsightedness caused by keratoconus. INTACS are replaceable if vision changes, or removable if desired. The procedure has been FDA approved since august 2004.
• Corneal transplants (PKP and DALK) involve the removal of a damaged or diseased cornea and subsequent replacement with a donor cornea.
  • PKP  (Penetrating Keratoplasty) is the replacement of the entire cornea, all 5 layers, with a donor cornea.
  • DALK – (Deep Anterior Lamellar Keratoplasty), involves the replacement of the epithelium, Bowman’s layer, and the stroma, leaving the patients own healthy Descemet’s membrane and inner endothelium intact.  By retaining the inner two layers, the chance for graft rejection is eliminated. The downside to DALK is the difficulty of dissecting down to Descemet’s layer without puncturing it.

A new treatment option is corneal collagen cross-linking.

Corneal cross-linking – Involves treating the cornea with a combination of riboflavin drops (vitamin b-2), and ultraviolet-a light.

Corneal cross-linking strengthens the areas in the cornea that have been weakened thru progressive corneal thinning. It produces structural changes in the cornea via the production of strong chemical bonds between the collagen fibrils and their adjacent fibrils. The UV light induces this bond formation in the presence of riboflavin.

The subsequent stronger/stiffer cornea can then undergo laser vision correction or INTAC implantation. Treatment by corneal collagen cross-linking is now available in the United States and we are currently utilizing the only FDA approved cross-linking system.