What is the cornea?

The cornea is the outer layer of the eye and helps focus light onto the retina. It’s responsible for 2/3rd of the eye’s focusing power and in order to see clearly, it must be smooth and clear.  Just like a dirty car windscreen, you can’t see well through an unhealthy cornea – it will distort light causing blurred vision or glare.

What is keratoconus?

Keratoconus is a degenerative disorder that is sometimes hereditary. The cornea, normally shaped like a soccer ball, becomes weakened, and bulges out to become shaped like a cone or rugby ball. Sadly, this leads to blurred vision with an increase in light-sensitivity that is hard to improve with glasses or routine soft contact lenses.

Keratoconus often starts in puberty and worsens over time. If left undiagnosed and untreated, the advanced disease may eventually require a corneal transplant. As this is something best avoided, it’s important to diagnose and treat keratoconus early.

What is the treatment for keratoconus?

Surgical treatment for progressive keratoconus to improve the strength and stability of the cornea is called ‘corneal collagen cross-linking’ (CXL). Crosslinking for keratoconus involves using riboflavin eye drops and ultra-violet light to stop the corneal shape from worsening. Safety of the treatment has been well established through studies across the world. In most cases, cross-linking successfully prevents further deterioration of the condition.

Do I need corneal surgery or transplant?

When the cornea is severely damaged through injury or disease and vision is affected, corneal transplant (or keratoplasty) may be recommended. During this procedure, all or part of the damaged cornea is replaced with healthy tissue from an organ donor. You may require corneal surgery if you have:

  • Scarring from infections

  • A hereditary condition such as Fuchs’ dystrophy and other corneal dystrophies

  • An eye disease such as advanced keratoconus

  • Thinning of the cornea and irregular shape

  • Corneal damage from an eye injury

  • Excessive swelling / decompensation of the corneal following previous multiple eye surgeries

Rest assured, if you’re facing the possibility of a corneal transplant operation, your eye specialist will take you through a thorough screening and consultation process, addressing all your questions and concerns. Detailed discussion ensures there are no surprises. Your specialist will make sure you feel informed and comfortable at every stage.

Am I suitable for corneal cross-linking surgery for keratoconus?

If you’re diagnosed with keratoconus, your eye specialist will assess your suitability for corneal cross-linking by detailed assessment and corneal tomography/topography to ensure your eyes are safe for the procedure. Even teenage patients can have the procedure, which is non-invasive, painless, and carried out under local anaesthetic drops while awake.

Can I have laser eye surgery to improve vision if I have keratoconus?

While LASIK is usually contraindicated (inadvisable) in keratoconus, for some suitable patients, your eye specialist can combine topography guided PRK laser treatment with crosslinking to improve vision. As structural changes occur during laser treatment, the aim of combining it with the strengthening effects of crosslinking helps to neutralise this effect. This can be done according to one of the following two protocols:

  • The Cretan Protocol – using laser for PRK to remove the skin of the eye instead of using alcohol during cross-linking has been shown to improve eyesight in selective groups of patients.

  • The Athens Protocol – combining PRK with crosslinking for mild to moderate keratoconus. Suitability for combined treatment is decided on the basis of a corneal scan (topography) and your spectacle or contact lens prescription (i.e. the amount of refractive correction required).

Note: The aim of combined treatment is to improve the quality of vision with or without glasses. It is not to make you independent of glasses which is the case in routine laser refractive surgery patients. Only mild to early moderate keratoconus patients can benefit from this treatment and suitability is decided by your specialist on a case by case basis after detailed assessment.

FAQs

Cross-linking reduces or halts the rate of progression of keratoconus.

The purpose of treatment is to stabilise the cornea rather than improve your vision and help you avoid major surgery like corneal transplantation in the future.