What is Keratoconus?
Keratoconus is where the front surface of your eye (the cornea) thins, affecting its natural shape. Ordinarily your cornea is round (like the surface of a football), but the thinning of the cornea in a keratoconic eye causes it to bulge, and become more cone shaped (like the end of a rugby ball). It is usually spotted when a person is in their late teens/early 20s, and is much more common in men.
The cornea is a clear dome that sits on the eye, and helps to direct light to the correct place at the back of the eye (retina). When this dome is misshapen, the light doesn’t focus on the retina correctly, and images can appear blurred. When this happens for people with keratoconus, it is known as “irregular astigmatism”.
What causes Keratoconus?
Nothing can be directly linked to keratoconus, but it is often associated with:
- Eye rubbing
- Ultra violet rays
- Longstanding use of poorly fitting contact lenses
- Frequent eye irritation
Symptoms of keratoconus
- Keratoconus can cause myopia and astigmatism, due to the cornea changing shape.
- Glare and sensitivity to light are another symptom of keratoconus. In bright conditions, more light is entering the eye, and being scattered rather than focusing correctly on the retina, making bright light especially harsh.
- Frequent changes to a person’s vision, resulting in a new prescription and glasses each time an eye test is performed .
How to correct keratoconus
There are several different methods of treating the symptoms of keratoconus, depending on how progressed the condition is, some of the most common are;
- Glasses- As the condition progresses, the lenses in your glasses may get thicker, due to needing a stronger prescription. This can cause distorted vision when looking out the side of your glasses. Therefore, you may wish to consider being fitted with contact lenses.
- Contact lenses- Rigid Gas Permeable lenses (RGP lenses), are one of the most common lens type for correcting keratoconic vision. RGP lenses are made from thicker plastic than soft lenses. Their stability provides a rounder shape over the cornea when worn, allowing the light entering your eye to focus correctly. Other lens types that are used in the correction of Keratoconus are;
Scleral lenses – A larger soft contact lens that can provide vision correction and typically more comfortable than RGP lenses
Hybrid lenses – A rigid centre to the lens to hold the cornea’s shape, with a soft outer area to provide comfort to the wearer
Soft contact lens – Typically used when a very mild form of Keratoconus is found and in some cases are worn under a RGP lens to increase comfort levels.
Corneal transplant- If the cornea becomes too steep, you may need to have a corneal transplant. This only happens in around 10-20% of people with keratoconus.
Typically, the progression of keratoconus stabilises during adulthood. You will need to still use vision correction for this condition, however changes in your vision are likely to be subtle and less frequent.
While there are many options available to improve Keratoconic vision, ever person with this condition is unique. Consultation and monitoring from an eye care professional will ensure that the most suitable correction method available and prescribed at every stage of the condition.