Part of the Good Vision for Life Series – Keratoconus – Fact Sheet.
What is it? How do I know if I have it? How can I treat it?
What is keratoconus?
Keratoconus (literally, conical cornea) is a thinning of the central zone
of the cornea, the front surface of the eye. The normal pressure within
the eye makes the thinner area of the cornea bulge forward slightly.
What causes keratoconus?
Keratoconus is an inherited disorder that occurs in about one in
3,000 people. It is a recessive condition requiring genetic factors to be
inherited from both parents, so the chances of the children of a person
with keratoconus also having the condition are low – about one in 50.
It is sometimes associated with other conditions such as allergies,
infantile eczema, asthma, reduced night vision, double jointedness and,
in rare instances, with occasional short bouts of chest pain. It mostly appears in people with a family history and in people who often vigorously rub their eyes.
What do people with keratoconus experience?
Keratoconus usually becomes apparent between the ages of 10 and 25
years. The initial symptom of keratoconus is blurred vision, which is
caused by short-sightedness and astigmatism. These are caused by the
cornea changing shape as it bulges forward. At this stage, good vision
can generally be obtained with spectacles.
As keratoconus progresses, the shape of the cornea becomes irregular
and it is not possible to correct the vision with spectacles alone. In
such cases, rigid contact lenses can be used to provide good vision. The
contact lenses essentially provide a new, regular front surface for the
eye, eliminating the distortions caused by keratoconus.
Because the cornea continues to change shape, it is important for
people with keratoconus to have regular eye examinations to ensure
that their contact lenses fit correctly. A poorly-fitting contact lens can
cause abrasions and scarring.
Can keratoconus be treated?
Because keratoconus is a genetic condition, it cannot be cured but
spectacles and specially fitted hard contact lenses can give good vision. In about 15 per cent
of cases, surgery in the form of a corneal graft may be required. In this
procedure, the thinned area of the cornea is removed and replaced
by normal tissue transplanted from a donor cornea. Corneal grafting
is used only when all other methods for correcting vision have failed
to provide good vision. The success rate for corneal grafts is extremely
high although most people will still need to wear spectacles or contact
lenses.
Collagen cross-linking is a therapy that uses administration of vitamin
B12 and UV light to strengthen the structure of corneas affected
by keratoconus. Ophthalmologists (eye surgeons) may carry out
this procedure to slow the progression of keratoconus.
For more information and to book a consultation, contact us at Vision Excellence.
Visit keratoconus.org.au for more information on the condition
