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 deflects light as it enters the eye on its way to the light-sensitive retina, causing distorted vision. Keratoconus can occur in one or both eyes and often begins during a person's teens or early 20s.

Keratoconus can be difficult to detect, because it usually develops slowly. However, in some cases, keratoconus may proceed rapidly. 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.

Glare and light sensitivity also may occur. Often, keratoconic patients experience changes in their eyeglass prescription every time they visit their eye care practitioner. It is not unusual to have a delayed diagnosis of keratoconus, if the practitioner is unfamiliar with the early-stage symptoms of the disease.

New research suggests the weakening of the corneal tissue that leads to 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 is also associated with overexposure to ultraviolet rays from the sun, excessive eye rubbing, a history of poorly fitted contact lenses and chronic eye irritation.

In the mildest form of keratoconus, eyeglasses or soft contact lenses may help. But as the disease progresses and the cornea thins and becomes increasingly more irregular in shape, glasses and soft contacts no longer provide adequate vision correction. If eyeglasses or soft contact lenses cannot control keratoconus, then rigid gas permeable (RGP or GP) contact lenses are usually the preferred treatment. Their rigid lens material enables GP lenses to vault over the cornea, replacing its irregular shape with a smooth, uniform refracting surface to improve vision.

But RGP contact lenses can be less comfortable to wear than soft contacts. Another treatment option is the semi-sclera lenses one of which is Maxim lenses. These lenses are slightly larger than a standard soft contact lens but made out of the same material as a traditional Rigid Gas Permeable.

With such a large diameter the edge of the contact lens does not touch the cornea providing greater comfort. The large size also decreases the movement of the lens which also relieves some of the discomfort associated with traditional rigid gas permeable lenses.

The Maxim design performs very well on irregular corneas including keratoconus, corneal trauma, pellucid marginal degeneration, penetrating keratoplasties. It incorporates a proprietary multiple posterior curve system to obtain corneal alignment. Patients who wear Maxim will have exceptional comfort and clarity throughout the day.

Intacs, or corneal inserts, received FDA approval for treating keratoconus in August 2004. These tiny plastic inserts are placed just under the eye's surface in the periphery of the cornea and help re-shape the cornea for clearer vision. Intacs may be needed when keratoconus patients no longer can obtain functional vision with contact lenses or eyeglasses.

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 10 minutes. Intacs might delay but can't prevent a corneal transplant if keratoconus continues to progress.

Once the patient reaches the point where contact lenses or other therapies no longer provide acceptable vision a corneal transplant will be necessary. The last remedy to be considered may be a cornea transplant, also called a penetrating keratoplasty (PK or PKP). Even after a transplant, you most likely will need glasses or contact lenses for clear vision.