Keratoconus is a progressive eye disease that causes the cornea to weaken and become conical in shape.
The cornea is the clear front surface or ‘window’ of the eye. In people with keratoconus, the cornea develops an irregular shape, which eventually affects your vision. Most people with keratoconus begin to develop the condition in their late teens or early 20’s.
The most obvious symptom of keratoconus is a conically shaped cornea. This usually occurs in both eyes, but may only affect one eye. It may also affect one eye more than the other.
The conical shape makes the cornea appear to ‘bulge’ from the eye socket. However, because the disease develops over time, it can be difficult to spot in its early stages.
Once the cornea begins to change shape, vision is usually affected. Because the cornea does much of the eye’s focusing, a change in shape results in blurred vision, and sometimes light sensitivity and ghost images. As keratoconus progresses, you may notice that glasses become less effective at improving your vision. Contact lenses can also become less effective, and uncomfortable to wear, as the cornea becomes more conical.
Causes of keratoconus
It is not known exactly what causes keratoconus. However, it is thought to be an inherited condition, so you’re more likely to have keratoconus if one of your parents has the disease. New Zealand is also known to have a relatively high prevalence of keratoconus, compared with other countries.
Some studies have connected keratoconus with conditions such as asthma and eczema, and also with excessive eye rubbing, and badly fitted contact lenses.
Keratoconus treatments are varied, and include contact lenses, corneal implants and corneal transplants. An advanced new treatment called corneal collagen cross-linking has been shown to stop and even reverse the effects of keratoconus, and is also now available at Eye Institute.