Keratoconus

Keratoconus is a condition affecting the cornea of the eye, which is the clear front surface of the eye. ‘Keratoconus’ literally means ‘conical cornea’ and describes a cornea that has thinned and distorted into a cone shape. As the cornea is the major focussing surface of the eye, this distortion affects your vision.

The incidence of keratoconus is approximately 1 in 2000 and often begins during puberty. It tends to progress slowly and then stabilise, although the degree of progression is different for each individual. The cornea may also become scarred over time, although this does not occur in every case.

The symptoms of early keratoconus are generally much the same as that of someone needing glasses – objects appear out of focus and blurred. The difference is that when you visit your optometrist to have your eyes tested, spectacle lenses often do not allow sharp focus, even with the best possible lenses in front of your eyes.

Diagnosis

If we suspect you have keratoconus, we will use an instrument called a topographer. This will show us a ‘map’ of your cornea and highlight any areas that are distorted. There are different types of keratoconus and this ‘mapping’ gives us as much information as possible so we know how best to treat it.

Treatment

There is no treatment at present that will cure keratoconus but it can be successfully managed. We mainly concentrate on improving the distorted vision, and quite often the most successful way to do this is to use Rigid Gas Permeable (RGP) contact lenses. As the name suggests, these have a rigid structure unlike the more common Soft contact lenses which are very flexible. The rigid contact lens can ‘vault’ over the cornea creating a smooth, uniform surface which enables the eye to focus better.

Fitting contact lenses for keratoconus is not an easy procedure; there is no one lens that will suit everyone. Here at R. J. Holmes Opticians we have been fitting lenses for keratoconus for many years and have gained a wealth of experience.

Other Treatments

In very severe cases of keratoconus, a corneal transplant may be recommended. This is usually recommended in cases where the cornea has become very scarred and is no longer clear in the centre. If this occurs, contact lenses no longer help as the scarring will physically obstruct good vision.

There is also a relatively new procedure called corneal collagen cross-linkage. This is a procedure performed by an Ophthalmologist and requires local anaesthesia. It involves the application of Riboflavin (vitamin B2) drops to the eye and then exposing it to ultraviolet light. The procedure aims to stabilise the cornea, and thus prevent further changes to its shape.  Occasionally, the procedure will also improve the shape of the cornea, making it more regular, but this does not always happen; the main aim is to prevent the keratoconus progressing further.

At present, this procedure is not widely available on the NHS and most people wanting to pursue this course do so privately. Not everyone is suitable for the procedure and at present the long term effects are as yet unclear.