Keratoconus is an inherited eye condition that affects the cornea. It leads to reduced vision even when wearing glasses or contact lenses.

Key points

  • Keratoconus is an inherited eye condition that affects the cornea. The cornea is the clear tissue that covers the front of your eye.
  • The normally round cornea becomes thinned, distorted and irregular. This leads to reduced vision.
  • Initial symptoms can be slight blurring or distortion of vision even when wearing glasses or contact lenses. Other symptoms include increased sensitivity to glare and light and as it progresses, vision may become more distorted.
  • Treatment depends on the severity of the condition and ranges from glasses or contacts, through to surgery.

What causes keratoconus?

The cause is unknown, but keratoconus is seen to have a genetic component, which means you inherit it from a parent. New Zealand has one of the highest proportional numbers of keratoconus in the world. It is more prevalent in Maori and Pacific Island males.

The cornea is the transparent front surface of the eye. In keratoconus, the cornea becomes thinned, distorted and irregular (cone-shaped). This abnormal shape prevents the light entering your eye from being focused correctly on the retina and causes distortion of vision.

It also has a link to allergic conditions such as atopic eczema and eye rubbing. The condition usually happens in the late teens to early twenties; however, it can be present at any age. It is a progressive disorder and can happen rapidly or take years to develop. It commonly affects both eyes, although sometimes only one eye is affected.

What are the symptoms of keratoconus?

Symptoms include:

  • nearsightedness
  • astigmatism
  • blurred vision – even when wearing glasses 
  • glare at night
  • eye rubbing
  • light sensitivity
  • frequent prescription changes in glasses and contact lenses

How is keratoconus diagnosed?

If you are concerned that you might have keratoconus, it is important to see your optometrist for an eye examination

How is keratoconus treated?

Treatment of keratoconus depends on its severity. Generally, the management and treatment options for keratoconus can be divided into three categories:

Glasses or soft contact lenses

In mild cases, vision can be corrected using glasses or soft disposable contact lenses

Custom Made Rigid Contact Lenses (RGP)

In moderate to severe cases of keratoconus, the cornea becomes abnormal in shape that glasses won’t provide clear vision. In these cases, a rigid contact lens is required to provide a new regular optical surface to correct vision. These lenses are custom-made to the shape of the cornea. Often, where vision can’t be improved with spectacles, contact lenses are funded by subsidy. Rigid contact lenses are the most common form of correction for keratoconus.


In progressive keratoconus, corneal collagen cross-linking is now available. This works by stabilising the cornea and preventing progression. In severe cases, when vision does not improve with glasses or contact lenses, surgery in the form of a corneal transplant may be recommended. Surgery is performed by an opthlamologist, usually in the hospital system. We can discuss this option with you, and refer as necessary.


A contact lens subsidy may be available, which will assist with the costs of contact lens fitting and lenses. This subsidy also contributes to replacement lenses due to loss, damage, or change.

Contact us to find out more about how we can help you from diagnosis to treatment of keratoconus.