People with keratoconus have an irregularly shaped cornea. Instead of a perfect spherical form, the sphere is bulged out and may sometimes even be conical. As the cornea is the primary refractive component of the eye, an altered shape has significant implications for the eyesight. The cause of this condition is an improperly formed structure of the corneal tissue, resulting in the loss of its solidity. In most cases both eyes are affected.
Keratoconus often only becomes evident after puberty. In less than 10% of patients, the condition is hereditary. People with keratoconus often also suffer from allergies or eczema and have sensitive, itchy eyes.
The treatment is mainly focused on improving sight. In the case of incipient keratoconus, special rigid gas-permeable lenses will be tried. There are also several specialized keratoconus lenses. If an eye has a sensitivity reaction to rigid, gas-permeable lenses, then alternatively, what is known as a ‘piggy-back’ system can be used. This involves a rigid lens being placed on top of a soft contact lens. In cases where corneal rigid gas-permeable lenses are capable of improving vision, but cannot be tolerated, scleral lenses may be the answer. These lenses are large and rest on the sclera (white surface) of the eye.
Patients who can no longer tolerate contact lenses, will in most cases require a corneal transplant. Following the transplant, either a pair of glasses or contact lenses will once again be necessary. These lenses will always be rigid, gas-permeable lenses.
Ongoing research is being conducted in order to provide alternatives to corneal transplants. Please note that treatment with an excimer laser is not an option for keratoconus patients.
The condition of the cornea needs to be monitored regularly. For this to be achieved, close cooperation between optometrist and ophthalmologist is essential. It is important to carry out routine examinations during this period. Due to the fact that the corneal surface is subject to change, it may be necessary to adjust the fitting of the lenses. For this reason, it is most important to consult a practice with sufficient experience in the medical application of contact lenses.