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Keratoconus (ker-uh-toe-KOH-nus) is a condition estimated to affect as many as 1 in 375 people. It’s an eye disease that alters the quality and shape of your cornea (the clear, usually dome-shaped front surface of your eyeball), causing blurred vision and sensitivity to light and glare. While the exact cause remains unknown, fortunately, treatment options are plentiful and varied depending on the severity of the condition.

1. Keratoconus – what’s happening in your eye?

With keratoconus, the usually round cornea becomes thin, distorted and cone-shaped. As a result of this irregular shape, it can’t perform its job properly. When this refractive process cannot be carried out correctly, the images passed to the retina and transmitted to the brain become distorted and blurred.

2. What causes it?

Several factors appear to contribute to keratoconus, but an exact cause is yet to be pinpointed. Genetic and environmental factors are thought to be critical contributors:

  • Family history – around 1 in 10 people with keratoconus have a blood relative with the condition.
  • Eye rubbing – rubbing your eyes vigorously can cause minor trauma to the cornea. Eye rubbing can occur in people with irritated eyes from poorly fitted contact lenses or symptoms of things like hay fever, eczema and asthma.
  • Oxidative stress – the cornea creates harmful by-products (free radicals) as do all tissues in the body. A healthy cornea can neutralise these, but in keratoconus sufferers, it looks like this is compromised, leading to oxidative stress (an imbalance of free radicals and antioxidants in your body). As a result, the structural part of the cornea becomes weakened and more prone to thinning and bulging.
  • Endocrine involvement – generally first detected during puberty and progressing quickly during pregnancy, it’s thought the endocrine system (the glands responsible for growth, development and reproductive hormones) has some involvement in the condition. What, exactly, is yet to be discovered.
  • Underlying disorders – certain conditions like Down syndrome, Ehlers-Danlos syndrome, Marfan syndrome, sleep apnoea and connective tissue disorders have been linked to keratoconus. However, a direct cause-and-effect relationship hasn’t been established.

3. Symptoms to be aware of

Typically developing in the teenage years with progression halting around the age of 30, the symptoms of keratoconus range from mild to severe and can change as the disease progresses. Recent studies have shown that men, African Americans and Latinos are at greater risk, while women, Asian Americans and people with diabetes appear to have a lower risk.

Here are the four most common symptoms:

  1. Blurred or distorted vision
  2. Sudden clouding or worsening vision
  3. Increased sensitivity to bright light and glare (this can become particularly obvious when driving at night)
  4. Frequent changes in eyeglass or contact prescriptions

Treatment options

There are several options available to treat and halt the progress of keratoconus, based on the severity of the condition and the disorder’s progression. The most common forms of treatment are broken into non-surgical and surgical:


  • Traditional eyeglasses or soft contact lenses – with only mild symptoms, vision can be improved with prescription lenses. However, as the condition progresses, the prescription will need to change.
  • Rigid lenses – these can help reshape the cornea and are custom-designed to fit. They provide good vision correction but can become uncomfortable to wear for long periods.
  • Piggyback contacts – also known as ‘tandem’ lenses, combining a hard contact lens placed over soft lenses
  • Hybrid lenses – these have a rigid centre with a soft ring around the outside, providing the comfort and stability of a soft lens with the clear vision of a rigid centre.
  • Scleral lenses – larger contact lenses that rest on top of the sclera (whites of the eyes) without touching the cornea. Due to their size, they need to be filled with saline before applying. They can be more challenging to apply and remove, but offer great results for most.


Corneal crosslinking

Corneal crosslinking (CXL) is a relatively new treatment option that is quick and less invasive.

  • Before the procedure, the patient will be given local anaesthetic drops to numb the area.
  • Vitamin B2 drops are placed into the patient’s eye, and the cornea is then exposed to UV rays.
  • This combination forms a chemical reaction that hardens and strengthens the cornea, halting the progress of keratoconus.
    CXL does not reverse changes that have already occurred. To help with the healing process and to make the eye more comfortable, a contact lens will be placed on the patient’s eye after the treatment.

Intrastromal corneal ring segments

Clear, arc-shaped implants known as ICRS or Intacs are surgically placed on the outer edge of the cornea to remodel, flatten and create symmetry in the cornea.

This reduces distortion and helps improve vision, but most patients will still require glasses or contact lenses after the treatment.

Corneal transplants

When other treatments are no longer viable options, an eye specialist may recommend a corneal transplant.

Dating back to the early 1900s, a corneal transplant involves replacing a patient’s damaged cornea with healthy donor corneal tissue (the National Eye Bank provides human tissue after careful quality screening).

Different procedures can be used, and the surgery is typically reserved for people with severe keratoconus who can’t tolerate or haven’t responded well to other treatments.

Early treatment equals good eye outcomes

The causes, treatments and diagnostics of keratoconus are continually being researched and developed, and with timely treatment, most people will have good outcomes.

If you’re experiencing any vision issues or suspect you may have keratoconus, booking an appointment is the best thing you can do. Early treatment can help decrease the severity and prevent worsening symptoms.

Auckland Eye is well-equipped with the most advanced technology, knowledge and training to diagnose and treat keratoconus changes to the eye, meaning you’ll benefit from the best possible visual outcomes.

If you have a question or would like to book an appointment, please contact our friendly specialist team on 0800 AKL EYES or email to

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