In New Zealand approximately 1 in 1000 people have keratoconus. Keratoconus is a progressive disease affecting the cornea that causes poor vision that often cannot be adequately corrected with glasses.
Keratoconus is most commonly managed using contact lenses and, fitted correctly, these can restore a normal level of vision. Keratoconic contact lens fitting is often challenging and is best performed by an optometrist with specialist experience in dealing with Keratoconus.
Michael has over 15 years’ experience in the management of Keratoconus including options that you may not have thought possible.
Keratoconus is caused by thinning of a portion of the cornea (generally just below the pupil). This causes the thinned area to bulge forward in a characteristic cone shape. Because the cornea is the front lens of the eye this distortion affects vision by creating irregular astigmatism.
Currently there is no cure for keratoconus but evidence suggests a strong link between eye rubbing and allergy and keratoconus.
Most allergic eye conditions cause the eyes to itch. A natural reaction to that itching is to rub your eyes. Unfortunately this causes cells within the eye to release more itch causing histamine which only exacerbate the problem. In some, genetically predisposed people, this starts a cascade of chemical events that cause the cornea to thin and ultimately leads to keratoconus.
It is currently believed that better control of allergic eye disease has the potential to prevent keratoconus from developing. We encourage patients with keratoconus to make sure that their children are seen by an optometrist if they show any signs of allergies such as hay-fever or asthma and particularly if they demonstrate a tendency to rub their eyes vigorously.
For those with early keratoconus glasses and conventional soft contact lenses may be sufficient to restore very close to normal vision however for those with more advanced disease these may not provide adequate clarity.
In these situations specialty contact lenses are the option of choice and there has been considerable progress in this field in recent years.
Soft contact lenses: new lenses such as the Kerasoft IC (Irregular cornea) are able to provide good comfort and surprisingly good vision by using silicone hydrogel materials that do not conform to the shape of the distorted cornea and aberration control optics to reduce the amount of ghosting around images.
Speciality RGP (Rigid Gas Permeable) lenses: such as the Rose K 2 remain a mainstay of the contact lens management of keratoconus as they provide the optimum combination of visual clarity and eye health. These lenses should only be fitted by an experienced contact lens specialist.
Semi-scleral lenses: are an option for those who are intolerant to the smaller RGP lenses. They are typically more comfortable than RGPs but need to be fitted with extreme precision to ensure they do not compromise the cornea.
Hybrid Lenses: for mild to moderate keratoconus these are an older option given a new lease of life by blending higher oxygen transmission materials in a soft “flange” around the outside of a conventional RGP lens.
The best way to determine which option is best for your needs is to come in for a consultation with Michael and together we will tailor a solution for you.
