Keratoconus
FAQ and details of the corneal collagen crosslinking trial at the Royal Victorian Eye and Ear Hospital
What is keratoconus?
Keratoconus is a thinning of the central zone of the cornea, the front surface of the eye. As a result of this thinning, the normally round shape of the cornea is distorted and a cone-like bulge develops, resulting in significant visual impairment.
What causes keratoconus?
The cause of keratoconus remains unknown, although recent research seems to indicate that it may be genetic in origin. Certainly, some cases of keratoconus have a hereditary component and studies indicate that about 8% of patients have affected relatives. If there is no evidence of keratoconus in successive generations of a family, there is less than a 1 in 10 chance of the children of a person with keratoconus also having the condition. Excessive eye rubbing has also been implicated as a causative factor.
How common is keratoconus?
Keratoconus is estimated to occur in 1 out of every 2000 persons in the general population. There appears to be no significant preponderance with regards to either men or women.
What are the signs and symptoms of keratoconus?
The initial symptoms of keratoconus are usually a blurring and distortion of vision that may be corrected with spectacles in the early stages of the condition. Frequent changes to the spectacle correction may be required as the cornea becomes progressively thinner.
What is the usual age of onset of keratoconus?
The onset of keratoconus can be anywhere between the ages of 8 and 45. In the majority of cases, it becomes apparent between the ages of 16 and 30 years.
Does keratoconus affect both eyes?
Yes, keratoconus generally affects both eyes. Only in a very small percentage of cases (<1%) is there just the involvement of one eye. Even though keratoconus is basically a bilateral condition, the degree of progression for the two eyes is often unequal; indeed, it is not unusual for the keratoconus to be significantly more advanced in one eye.
Is keratoconus associated with any other diseases or disorders?
Keratoconus has been associated with conditions such as hay fever, asthma, eczema, double jointedness, Down’s syndrome, Marfan’s syndrome and mitral valve prolapse.
Does keratoconus cause blindness?
Keratoconus does not cause total blindness. However it can lead to significant vision impairment resulting in legal blindness.
How is keratoconus treated?
In the early stages of the condition, spectacles are usually successful in correcting the myopia and astigmatism associated with the keratoconus. As the condition advances, the cornea becomes highly irregular and vision is no longer adequately corrected with spectacles. Rigid contact lenses are then required to provide optimal visual acuity. Soft contact lenses are usually not an option, as they cannot correct for the irregular astigmatism associated with the keratoconus. In about 15% of cases, the keratoconus progresses to the stage where corneal transplantation is required.