Keratoconus

keratoconus

In the last few weeks there have been a number of people who have come in for an eye check that have had keratoconus.

Keratoconus is often said to affect 1 in every 2000 of the population. Orange has a population of 40000, so there should be 20 people with keratoconus in our city.  Well, I’ve seen them all in the last month!

So what is Keratoconus?

If we have a look at the actual name, ‘kerato’ is the Greek word for cornea and ‘conus’ is Latin for cone.keratoconus  This is an eye condition where the cornea thins and becomes weaker causing it to lose its spherical shape and become more cone-like.

A cone-shaped cornea does a very poor job of focusing light at the back of the eye.  Thus, people with keratoconus have blurry distorted vision.

Unlike short or long-sightedness or astigmatism, keratoconus cannot be fully corrected with spectacles due to the irregular front surface of the eye.  Thankfully, this is not a blinding disease but often spectacles do not provide good enough vision to get a driver’s license.

People with moderate to severe degrees of this condition require hard contact lenses to correct their vision.  A good fitting hard contact lens provides a new smooth front surface for the eye enabling excellent vision.

Hard contact lenses have come a long way in the last decade and with the assistance of specialty equipment like a corneal topographer, a well-fitted comfortable lens can be obtained.

Treatment

Some very advanced cases of keratoconus may require a corneal graft.  Corneal grafts are reserved for keratoconics who have exhausted all other options to treat their keratoconus.  In most cases corneal graft surgery is successful however the graft usually only lasts a maximum of 20 years and there can be problems with rejection of the donor cornea.  Also, hard contact lenses are often still required to obtain good vision following surgery.

More recently a new procedure called collagen cross linking has become the first line of treatment for newly diagnosed sufferers.  Collagen cross linking is a procedure that strengthens and stiffens the cornea.  This has the effect of slowing or even stopping the progression of the disease.

Collagen cross linking does not reverse the changes that have already taken place, it just limits the progression.

Prevention 

The current thinking regarding the cause of keratoconus is that it has both genetic and environmental factors.keratoconus  There is often a family history of glasses (astigmatism, short sightedness) but also an environmental trigger that starts the keratoconic process.  The best-known trigger is eye rubbing.

Do not rub your eyes!  Especially ‘knuckle rubbing’.  If you or your child is an ‘eye rubber’, particularly if there is a family history of keratoconus or spectacles, you must make every effort to stop.  For the allergy-prone patient, this may involve eye drops, often required all year round.

Early detection is the other key factor to prevent vision loss due to this condition.  Now that collagen cross linking has been shown to slow or even halt the cornea changing shape, the earlier you are diagnosed with keratoconus the earlier the process can be stopped.  Ideally, someone with early keratoconus will have collagen cross linking while they still have good vision.

If there is a family history of keratoconus or you or your child is an ‘eye rubber’, regular eye tests are essential.  Corneal topography will detect even the very early stages of keratoconus and treatment can be initiated.

 

Written by Justin Clunas

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