Keratoconus

Keratoconus is a condition where the cornea (front, clear part of the eye) thins and becomes cone shaped. In addition to the cone shape, the cornea becomes irregular (astigmatic) resulting in a distorted image being projected onto the retina. Glasses may not adequately correct vision as they can for most people with refractive errors, and rigid contact lenses may be required to give sharp vision. There is no known cause of keratoconus, but it may be inherited in some cases, and is often associated with allergic conditions and eye rubbing.

Often patients are first suspected of having keratoconus due to increasing spectacle blur or progressive changes in their spectacle prescription. Patient’s generally report progressive distortion over years, and sometimes with glare issues too. Initially keratoconus may affect only one eye, but generally both eyes are affected, one more severely than the other.

Males and females are equally affected. The condition generally commences at puberty and can progress into the thirties. Between these ages progression is impossible to predict, and some patients may be minimally affected. However young patients with advanced keratoconus are more likely to progress to the point where they may require surgical intervention.

Their Optometrist may find that the best refraction still yields poor vision. Keratoconus can be diagnosed with the use of corneal topography, and sometimes with a slit-lamp examination in more advanced cases.

Initially glasses or soft contact lenses can be prescribed to correct the distortion. As the condition progresses, specialty contact lenses are required to improve vision. If lens correction is not suitable then corneal transplantation is possible to correct the abnormal corneal shape.

Collagen cross-linking is a relatively new treatment modality to halt the progression of keratoconus. This technique changes the intrinsic biomechanical properties of the cornea, increasing its strength considerably and thus arresting the progression of keratoconus.

While still not a cure for the condition, collagen cross-linking aims to halt the progression of keratoconus, and so prevent further deterioration in vision and the need for corneal transplantation. Only patients with documented progression of keratoconus are suitable for this treatment. In patients with advanced keratoconus and extremely thinned corneas, this treatment may not be possible. In such a situation other alternatives such as forms of corneal transplantation can be considered.