Keratoconus is an eye condition that develops when your cornea (the transparent dome at the front of your eye) thins and gradually bulges outwards into a cone shape. The cone-shaped cornea can then cause astigmatism (blurred vision). It may also result in short-sightedness, which can get worse over time. The condition usually affects both eyes, though it tends to affect one eye more than the other. Typically, keratoconus develops in teenagers and young adults between the ages of 10 and 25; and can progress slowly over a period of around 10 years.
Keratoconus
Also known as: Bulging cornea, Conical cornea
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Keratoconus symptoms include:
- Blurred, distorted or clouded vision
- Increased sensitivity to bright light and glare (photophobia), which can cause problems with night driving
- Seeing halos around bright lights
- A need for frequent changes in eyeglass or contact lens prescriptions due to a worsening of vision
- Double vision when you look out of just one eye
- Headaches associated with eye pain
- Red and inflamed eyes
If keratoconus is left untreated, the symptoms may change as the condition progresses.
What causes keratoconus?
The exact cause of keratoconus remains unknown, although it is believed that both genetic and environmental factors are involved.
It’s estimated that around one in 10 people with keratoconus will also have a first-degree relative with the condition. It is also believed that the predisposition to develop keratoconus is present at birth. However, keratoconus isn’t typically considered to be an inherited disease.
There are a number other of factors that may increase your chances of developing keratoconus, such as:
- Metabolic and chemical changes in the cornea due to unknown causes
- Having allergic conditions, such as hay fever, asthma and eczema
- Having conditions such as retinitis pigmentosa, Down syndrome, Ehlers-Danlos syndrome and Marfan syndrome
Will implantable ring segments replace my need for a prescription?
No, implantable ring segments do not contain a prescription and will not provide any form of vision correction other than that which comes from changing the shape of your cornea.
However, in some mild cases, they may eliminate the need for a prescription.
Can contact lenses control the progression of keratoconus?
Unfortunately, no. Contact lenses can improve your vision, but they cannot prevent the condition from getting worse.
To stop the condition from worsening, you will need to consider corneal cross-linking, implantable ring segments or having a corneal transplant.
When to see a consultant?
In the early stages of keratoconus, there may not be any noticeable symptoms. However, if the condition is left untreated, it can get worse over time and cause complications which may result in you needing surgery or having a loss of vision.
Therefore, whether you’re experiencing symptoms or not, it’s important to have regular exams with an optometrist so that keratoconus can be identified and treated early. That’s why you should book an appointment with an eye doctor regularly, and if you notice symptoms, immediately.
Keratoconus diagnosis
To diagnose keratoconus, an ophthalmologist will usually go through your medical history, family history of the condition and your symptoms.
They will then conduct one or more of the following tests to make sure they’re making the right diagnosis:
- Visual acuity tests – using an eye chart to assess the clarity of your vision, your optometrist will be able to make the right prescription for your glasses or contact lenses
- Refraction tests – where you look through different lenses to assess how your eye refracts (bends) light
- Slit-lamp examination – using a vertical beam of light on your cornea and a low-powered microscope, your eye specialist will evaluate the shape of your cornea and look for other potential problems in your eye
- Keratometry – by focusing a circle of light on your cornea and measuring the reflection, your optometrist can determine the basic shape of your cornea
- Corneal topography – which can be used to create a detailed map of your cornea and measure the thickness of the cornea
Wondering if you might have keratoconus? Book an appointment with one of the specialists at The London Clinic Eye Centre today.
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Keratoconus treatments
The treatment for keratoconus depends on how severe the condition is and how quickly it’s progressing. Depending on these factors, your treatment plan may include prescription lenses, corneal collagen cross-linking and surgery. Keep reading to find out more about these treatment types.
If you have mild to moderate keratoconus, your ophthalmologist may determine that eyeglasses and contact lenses are the most appropriate form of treatment. However, there are different types of lenses that may be prescribed to you, depending on the severity of your condition.
These include:
- Glasses or soft contact lenses – these are best for mild keratoconus, though your prescription will likely change as your condition progresses
- Hard contact lenses – for intermediate keratoconus, you may be prescribed hard, gas-permeable contact lenses, which can be made to fit your corneas
- Piggyback lenses – if you find hard contact lenses too uncomfortable, your ophthalmologist may recommend ‘piggybacking’ a hard contact lens on top of a soft one
- Hybrid lenses – these are contact lenses with a rigid centre and a soft outside to make them more comfortable to wear
- Scleral lenses – if the shape of your cornea has become very irregular in advanced keratoconus, these lenses are designed to sit on the white part of your eye (the sclera) without touching your cornea
If you have intermediate keratoconus, your doctor may recommend corneal collagen cross-linking. Before the procedure begins, you’ll be given a local anaesthetic, so you won’t feel anything.
During the procedure, the cornea is saturated with riboflavin (vitamin B2) eye drops before being exposed to ultraviolet light. This process strengthens the bonds between your cornea’s collagen fibres and surrounding proteins to prevent further shape changes to the cornea.
By stabilising the cornea early in the condition, corneal collagen cross-linking may help to reduce the risk of progressive vision loss.
There are two surgical options for keratoconus:
- Implantable ring segments – for mild to moderate keratoconus, your eye doctor may recommend a procedure during which they insert small synthetic rings into your cornea. The rings can help to flatten your cornea, improve your vision and make your contact lenses fit better. Sometimes, an ophthalmologist may choose to both implant ring segments and use corneal cross-linking to treat keratoconus
- Corneal transplant (keratoplasty) – for more severe forms of keratoconus which have resulted in corneal scarring, corneal thinning and poor vision, you may need to undergo a corneal transplant. Depending on the severity of your condition, your surgeon may choose to replace all or just part of your cornea with healthy donor tissue. Find out more about corneal transplants with The London Clinic Eye Centre.
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