Keratoconus is a degenerative eye condition in which the cornea gradually loses its curved shape and becomes increasingly conical. It is not that uncommon a condition, with estimates suggesting that between 1 in 500 to 1 in 1,000 people in the British Isles suffer with it to some degree. However, doctors are not yet completely sure what causes keratoconus, with genetic and environmental factors being considered possible factors. It may also be attributed to dysfunctional enzyme activity within the cornea.
Keratoconus is generally first diagnosed between the ages of 13 – 20 and if left untreated can make it difficult for a patient to read standard print or drive a car. However, there are a number of ways of treating the condition and preventing its progression.
Symptoms of Keratoconus
Patients who are suffering from keratoconus typically approach an optician after they notice a slight blurring of vision. However, the initial symptoms are similar to those of many other eye conditions, so it is not always diagnosed immediately. Rather, it is often marked by a rapid progression of symptoms, and after the preliminary blurring of vision, sufferers quickly begin to experience other symptoms including; rapid deterioration in vision, difficulty with vision at all distances, impaired night vision, multiple ghost images, and halos and distortion around light sources. Additionally, all symptoms are often much worse in low light conditions. Some patients develop eye strain or an itching sensation in the eye, but keratoconus is generally not painful, and whilst it usually does develop in both eyes, it doesn’t usually progress at the same rate in each.
How is Keratoconus Diagnosed?
Keratoconus is diagnosed through a number of tests including; a discussion of symptoms, use of a standard eye chart, checking of the eye using a keratometer and a retinoscopy. Further diagnostic techniques can include a slit lamp examination of the cornea or use of a keratoscope to provide a visual recreation of the surface of the eye.
Once a patient has been confirmed as suffering from keratoconus, their condition will then be categorised as mild, advanced or severe depending upon the steepness of the curve exhibited in the cornea.
Treatment Using Contact Lenses
For relatively new cases of keratoconus, contact lenses can help correct your vision. There is no one design of lens that best suits sufferers and which you choose will depend on what fits your eye, is comfortable to wear and achieves the desired results. However, it is considered best to visit an optician who has experience of fitting lenses for patients with keratoconus.
Soft lenses have become increasingly popular over the last year as they no longer simply drape over the misshaped cornea without properly correcting the vision. New technology allows them to correct vision and they are generally considered comfortable to wear.
Rigid Gas Permeable (RGP) lenses have been the standard type of lenses used for many years as they mask the misshapen cornea allowing a clear image to enter the eye. However, RGP lenses are generally not considered as comfortable to wear as soft lenses.
There is also the option of hybrid lenses which have an RGP centre with a soft edge, thereby combining the benefits of RGP and soft lenses, but as the disease progresses, lenses may no longer be suitable and patients may have to have a full corneal transplant.
Corneal Cross Linking
Corneal Cross Linking, often referred to as CXL, is a new and promising keratoconus treatment which appears to halt or significantly slow down the progress of the disease. It works by building up the strength of corneal tissue. Currently, this treatment doesn’t correct your vision but it does stop it getting any worse.
The CXL procedure involves polishing the surface of the cornea using a brush, vitamin B2 drops are then applied to the eye and the cornea is exposed to UVA light for up to 30 minutes. This strengthens the corneal fibres in the eye and prevents further bulging occurring.
CXL offers a number of benefits including; increasing the strength of the cornea, making it easier to wear contact lenses, preventing disease progression, deferring the need for corneal transplants and can reduce the myopia associated with the disease. The treatment is now available in a number of UK clinics, but as it is a relatively new procedure, you should look for an optical surgeon who has experience with this specific technique.