KERATOCONUS

Keratoconus is an eye condition where the front surface of the eye, the cornea, becomes thinner and bulges out. It often starts in late teens or twenties and can be progressive. The bulging of the cornea makes it difficult for light to focus sharply at the back of the eyes. As a result, vision gets distorted, often with multiple ghost images or shadows.

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Corneal topography (mapping) chart of a typical keratoconic cornea. The red area shows the area of steepening and thinning from keratoconus.

In the early stages, spectacles, or conventional soft contact lenses may give satisfactory vision. However, as the condition progresses, rigid gas permeable contact lenses, or specialist soft lenses are often needed. Contact lenses are very effective in restoring normal vision except in very advanced cases where corneal transplant surgery may be needed.

We have a particular interest and expertise in contact lenses for keratoconus. The founder of the practice Tony Shephard devoted his professional life to developing contact lenses to correct keratoconus and other corneal irregularities. See our specialist contact lenses section for further details about contact lenses we supply for keratoconus.

CAUSES OF KERATOCONUS

Although the exact cause of keratoconus is not known, there is definitely a genetic element, although the majority of sufferers don’t have any close relatives with the condition. People with certain health issues like atopies (asthma, eczema, hay fever) have a higher risk of developing keratoconus, and there is believed to be a link with eye rubbing. Hence, people diagnosed with keratoconus are strongly advised to avoid intense eye rubbing.

HOW COMMON IS IT?

There is some debate on this with current estimates ranging from 1 in 1,000 to 1 in 2,000. The incidence in Asian population is considerably higher, possibly 1 in 800.

CAN IT BE TREATED?

There is no cure for keratoconus as such, but there is the possibility of stabilising it and preventing further progression with a new procedure called corneal crosslinking, also known as CXL. It is generally a very effective procedure in stabilising the condition and should be considered when there is evidence of progression. Unfortunately, provision of crosslinking under NHS is currently somewhat haphazard, and a lot of people opt to have it done privately due to NHS funding constraints.

If you have been diagnosed with keratoconus and you are concerned about your condition deteriorating, please contact us for further advice.

Hence, the modern approach to managing keratoconus is based on providing the appropriate optical correction depending on the severity of the condition and monitoring for progression with a view to carrying out crosslinking if any signs of progression.

Laser eye surgery is normally not a viable treatment as it causes further thinning of the cornea and is generally regarded as unsafe. However, some corneal surgeons and refractive surgery clinics offer topography-guided laser correction in conjunction with CXL, the so-called Athens Protocol. The idea is to use a laser to reduce the distortion in the central part of the cornea and carry out CXL at the same time to strengthen the cornea. If you are considering this, you are advised to consult an eye surgeon experienced in this field to assess your suitability.

Other novel treatments used for keratoconus include Kerarings and Ferrara rings. These are thin plastic semi-circular rings inserted into the cornea in an effort to make the corneal shape more uniform. This may be a useful option for people who are unable to tolerate contact lenses as it may make it possible to achieve satisfactory vision with spectacles.

If all options have been exhausted, and it has not been possible to improve the vision, then corneal transplant surgery may be the next step. It was estimated that about 20% of people with keratoconus would need corneal transplant surgery at some stage in their lives, but this figures is expected to reduce drastically with the advent of crosslinking treatment.

Traditionally, corneal transplant surgery involved replacing central 8-8.5mm diameter part of the cornea with donor tissue. This was “full thickness” where the entire corneal tissue was transplanted. Nowadays, a procedure called DALK is favoured where the bottom layer of the person’s own corneal tissue is preserved, and only the top layers are replaced with donor tissue. The benefit of this procedure is that it greatly reduces the risk of the body rejecting the new corneal tissue.

You can get more information on keratoconus at the following links: