Understanding Keratoconus: Causes, Symptoms, and Treatments

What is Keratoconus?

Keratoconus is a progressive eye condition characterized by the thinning and reshaping of the cornea, leading to distorted and blurred vision. As the cornea thins, it begins to bulge forward, adopting a cone-like shape. This condition can affect one or both eyes and is often asymmetric. Though relatively rare globally, with a prevalence of about 1 in 2000, New Zealand experiences a higher incidence of keratoconus compared to other countries.

Causes of Keratoconus

The exact cause of keratoconus remains unknown, but it is believed to involve both acquired and inherited factors. The condition often appears in individuals with allergies, asthma, or eczema, and there is a strong correlation with frequent eye rubbing. Typically, keratoconus develops between the ages of 10 and 25, and it is uncommon for the disease to progress after the age of 40.

Key Points:

  • Unknown cause: Combination of genetic and environmental factors.

  • Strong link to eye rubbing: Common in many sufferers.

  • Onset age: Between 10-25 years old.

 
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Signs and Symptoms

As the cornea becomes more cone-shaped, vision blurs and distorts. Common symptoms include double vision or ghost images in one eye, frequent changes in spectacle prescriptions, glare, and light sensitivity.

In mild cases, glasses or soft contact lenses can correct vision. However, moderate to severe cases often require specially designed rigid gas permeable (RGP) lenses.

Specialty Contact Lens Fitting

Fitting contact lenses for keratoconus patients is considered a specialty due to the irregular corneal shape. These lenses are designed to provide a stable back surface, a middle tear fluid layer to cushion and fill the gap, and a regular-shaped front surface to restore clear vision. There are a range of lens designs available. Many of our CCLS Optometrists Members are experienced in fitting keratoconic lenses.

Frequent follow-up visits are essential, as keratoconus can change quickly, necessitating regular lens adjustments to ensure good vision, comfort, and eye health. Poorly fitting lenses can lead to scarring, discomfort, and impaired vision.

In New Zealand, local district health boards offer a small subsidy for lenses and fitting fees for some keratoconus patients. Consult your optometrist for more details about this subsidy.

Corneal Crosslinking

In the early stages of keratoconus, corneal crosslinking is an effective procedure designed to halt the progression of the condition by making the cornea more rigid and less likely to distort. While it does not reverse existing changes, it is particularly beneficial for teenagers to prevent further progression.

Corneal Graft Surgery

Approximately 15% of keratoconus cases advance to a stage where corneal graft surgery is necessary. This surgery can significantly restore vision and has a high success rate. Post-surgery, some individuals may still require specialty contact lenses.

If you’re looking for an Ophthalmologist who’s experienced in the surgical management of Keratoconus, you can find them on our “Find an Expert” Page.

Importance of Regular Eye Exams

Given the hereditary nature of keratoconus, it is crucial for individuals with the condition to have their children’s eyes tested regularly. Early detection and treatment can significantly benefit and manage the condition effectively.

Want to know more?

Many of CCLS optometrists and ophthalmologists specialise in the management of Keratoconus. You can find one in your local area here