On Friday, 10 November the global community will acknowledge World Keratoconus Day in the hopes of increasing awareness and education about this rare, but potentially debilitating, eye condition.
Literally meaning “conical cornea”, keratoconus is a thinning of the central zone of the cornea, which is the clear window forming the front surface of the eye.
When this structure begins to thin, the normal pressure of the eye causes the cornea to bulge forward slightly, resulting in the initial symptoms of blurred vision caused by short-sightedness (myopia) and irregular astigmatism.
What causes keratoconus?
Keratoconus is an eye disorder that is probably caused by genetic and environmental factors.
It is traditionally thought to occur in about one in 2000 people, however a 2020 Australian study of young adults found prevalence to be much higher, about 1 in 84 people; this difference in data is most likely due to improved screening, awareness and understanding of this condition.
Keratoconus affects people world-wide, and the prevalence is different among different ethnic groups. For example, keratoconus is more prevalent among the Māori population within New Zealand, compared to the general population.
It is sometimes associated with atopic conditions such as hay fever, eczema and asthma. Other genetic diseases associated with keratoconus include Down's Syndrome, Marfan's Syndrome and Ehlers-Danlos Syndrome.
Keratoconus is also strongly associated with vigorous eye rubbing. Eye rubbing should be avoided at all costs as it can cause further weakening to already weak corneas. If you have keratoconus, you may not even be conscious of the habit.
Frequent rubbing may be related to allergies, lid hygiene or dry eye, so talk to your optometrist about ways to control these conditions, such as with anti-allergy eye drops or lid hygiene techniques.
The experience of keratoconus
The initial symptom of keratoconus is blurred distorted vision, and these symptoms usually occur in late teens or early adulthood. These issues are triggered by the cornea changing shape as it bulges forward.
Other signs include:
- A need for frequent updates in glasses prescriptions
- Increased sensitivity to bright light and glare, which can cause problems with night driving
- Frequent, vigorous ‘knuckling’ eye rubbing
As the condition progresses, the cornea continues to change its shape, which means that those affected need to be vigilant and proactive in maintaining their eye health.
However, it's worth noting that, for most individuals dealing with keratoconus, there's a silver lining on the horizon; by the time they reach the age of around 35 years, the condition often stabilises and does not continue to worsen.
Can keratoconus be treated?
Because keratoconus is genetic, it cannot be cured, however at the early stages spectacles and contact lenses can give good vision. The contact lenses prescribed are usually rigid, like a rigid gas permeable lens (RGP), hybrid lens (combination of a soft and hard lens) or a mini-scleral lens. All these special contact lenses 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, which could make the condition worse.
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. Fortunately, the success rate for corneal grafts is extremely high, although most people will still need to wear glasses or contact lenses.
Other therapeutic options for keratoconus management
For those who want to slow down the progression of keratoconus, collagen cross-linking is also a promising therapy.
This procedure involves the administration of vitamin B12 and exposure to UV light, which strengthens the structural integrity of the cornea affected by keratoconus.
As the cornea becomes stronger, the bulging of the cornea is prevented from getting worse.
Your optometrist can refer you to an ophthalmologist to discuss this option if there is evidence of keratoconus progression.
It is also important for patients with keratoconus to make sure they are getting their kids eyes checked regularly by an optometrist, as with early detection and treatment we can now limit the amount of people developing severe keratoconus and needing (the much more complicated) corneal graft surgery.
Prioritising proactive eye health steps
When it comes down to it, it's crucial to seek expert advice from an optometrist if you are concerned about your vision or already have a keratoconus diagnosis.
The condition may be an unwelcome presence but with the right approach and expert guidance, you can still enjoy a life with improved vision.
For more information and to discuss your specific needs, don't hesitate to reach out to your local optometrist.
You can find your closest optometry practice using our Find an optometrist search function.
This search tool will also let you find optometrists who offer more complex contact lens fittings for keratoconus (RGP, hybrid or mini-scleral fitting) or who have a topographer (a machine which captures a detailed shape map of the cornea, enabling earlier detection and monitoring of progression for keratoconus).