Keratoconus is a progressive eye disease in which the normally round cornea thins and begins to bulge into a cone-like shape. This cone shape causes distorted vision. As the disease progresses, vision will progressively deteriorate. Keratoconus usually begins during late teens or early 20s and can occur in one or both eyes.

Keratoconus signs and symptoms

As the cornea becomes more irregular in shape, it causes progressive nearsightedness and irregular astigmatism to develop, creating additional problems with distorted and blurred vision. Another problem is the increased sensitivity to light. At some stage, the corneal changes can happen fast, and the prescription has to be updated frequently.

What causes keratoconus?

According to research, keratoconus may be due to an imbalance of enzymes within the cornea. This imbalance makes the cornea more susceptible to oxidative damage from compounds called free radicals, causing it to weaken and bulge forward. Risk factors for oxidative damage and weakening of the cornea include a genetic predisposition, explaining why keratoconus often affects more than one member of the same family. Keratoconus can also be associated with overexposure to ultraviolet rays from the sun, excessive eye rubbing, a history of poorly fitted contact lenses,
and chronic eye irritation.

Keratoconus treatment

In the early stages, spectacles or rigid contact lenses can improve vision, but as the disease progresses, more advanced treatment options will have to be exercised.

Treatments for progressive keratoconus include:

• Rigid Gas Permeable contact lenses
Because spectacles and soft contact lenses often cannot provide adequate visual acuity in cases of keratoconus, rigid gas permeable contact lenses usually are the preferred treatment. RGP lenses replace the irregular shape of the corneas with a smooth, uniform refracting surface to improve vision. Fitting contact lenses on an eye with keratoconus often is challenging and time-consuming. You can expect frequent return visits to your Eye Care Professional to fine-tune the fit and your prescription, as the keratoconus continues to progress. RGP lenses will work up to a point when the better option will be scleral lenses.

• Scleral Lenses
These are large-diameter gas permeable contacts that vault the cornea and rest on the white (sclera) of the eye. These lenses don’t apply pressure to the eye’s cone-shaped surface, resulting in a more comfortable fit. These larger lenses are also more stable than conventional rigid gas permeable contact lenses, which move with each blink because they cover only a portion of the cornea. The visual outcomes with scleral lenses are often excellent and can be very rewarding for the patient.

• Corneal cross-linking
This procedure, also called corneal collagen cross-linking or CXL, strengthens corneal tissue to halt bulging of the eye’s surface in keratoconus. There are two versions of corneal cross-linking: epithelium-off and epithelium-on. With epithelium-off cross-linking, the outer layer of the cornea (the 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 cross-linking), the corneal epithelium is left intact during the treatment. Epithelium-on has less risk of infection, less discomfort, and one-day visual recovery. Corneal cross-linking may significantly reduce the need for corneal transplant, which is often the last resort. Using a combination of corneal cross-linking and Intacs implants also has demonstrated promising results for treating keratoconus.

The aim of corneal cross-linking is to strengthen the cornea by increasing the number of “anchors” that bond collagen fibres together. (Diagram: Boxer Wachler Vision Institute)

• Intacs
Intacs are clear, arc-shaped corneal inserts that are surgically positioned within the peripheral cornea to reshape the front surface of the eye for clearer vision. Intacs may be needed when keratoconus patients no longer can obtain functional vision with contact lenses or spectacles.

Several studies show that Intacs can improve the best spectacle-corrected visual acuity (BSCVA) of a keratoconic eye by an average of two lines on a standard eye chart. The implants also have the advantage of being removable and exchangeable. The surgical procedure takes only about ten minutes. Intacs might delay but can’t prevent a corneal transplant if keratoconus continues to progress.

• Corneal transplant
Some people with keratoconus can’t tolerate a rigid contact lens, or they reach the point where contact lenses or other therapies no longer provide acceptable vision. The last remedy to be considered may be a cornea transplant, also called penetrating keratoplasty. Even after a transplant, you most likely will need glasses or contact lenses for clear vision.


Ten years ago, keratoconus sufferers often found themselves destitute with no hope in sight of regaining clear, comfortable vision. Recent advances in technology and clinical procedures have drastically improved the outcomes for keratoconus.

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