What is keratoconus?
The cornea is the transparent dome-shaped window on the surface of the eye, overlying the coloured iris. Its smooth round surface is important for maintaining clear vision. In keratoconus the cornea becomes thin and distorted, eventually protruding forwards in a cone-like shape. It typically affects both eyes, but can often be quite asymmetric.
Why does keratoconus develop?
The causes of keratoconus are not very well understood. However there is a genetic tendency, so it can sometimes run in families. There is also an association with allergies and most people with keratoconus have itchy eyes and rub their eyes to some degree. Over several years the pressure on the eye from rubbing may contribute to distortion of the cornea.
Who gets keratoconus?
Keratoconus occurs in young people, often starting in the teens, or even younger. It usually progresses slowly, and then stabilizes in the thirties or forties. It affects males and females in all racial groups, although in New Zealand it is most common in the Maori and Pacific populations.
What are the main symptoms of keratoconus?
Keratoconus causes blurring and distortion of vision in one or both eyes. It often gets slowly worse over time, but occasionally causes quite a sudden deterioration in vision. People with keratoconus often have associated allergic conjunctivitis, which causes itchy eyes and eye rubbing.
What treatments can help with keratoconus?
In the early stages of keratoconus, glasses or soft contact lenses may help correct blurred vision. As the cornea becomes more distorted only hard contact lenses are able to improve vision. About 15% of people with keratoconus progress to the stage where corneal transplant surgery.
Corneal collagen cross linking (CXL) is an exciting new treatment for mild or moderate keratoconus. This uses a combination of ultraviolet light and vitamin B2 to stiffen the cornea, slowing or halting the progression of the disease. Our corneal surgeon can advise which treatment is most suitable for you.
Need more information?
Contact Eye Doctors
American National Keratoconus Foundation
This is the website of the National Keratoconus Foundation which provides resources and support for people with keratoconus.
www.keratoconus.asn.au
This is the Keratoconus Australia website which also provides useful resources and support for people with keratoconus.
Collagen Cross Linking for Keratoconus
What?
Corneal collagen cross linking (CXL) is an effective new treatment for keratoconus and other forms of corneal ectasia. A combination of ultraviolet light and vitamin B2 causes corneal collagen fibres to bond more tightly to each other. This stiffens the cornea, making it less prone to deformation and slows or halts the progression of corneal ectasia.
Why?
Keratoconus can cause significant loss of vision. By stabilising the cornea in the early or moderate stages of the disease, further vision loss can be prevented. About 50% of people also have some improvement, with flattening of the cornea, better unaided and corrected vision and improved contact lens tolerance. CXL also reduces the need for corneal transplant surgery, by preventing keratoconus from progressing to more advanced disease.
Who?
Collagen cross linking is suitable for adults and teenagers with mild or moderate keratoconus that has shown definite progression over a period of at least 3 months. This includes at least 1 dioptre of corneal steepening or refractive change. A clear cornea with a minimum thickness of 400 microns is required.
How?
CXL is performed by Dr Penny McAllum in the Eye Doctors clinic at Ormiston Hospital and Ascot Hospital. One eye of a patient is treated at a time. After local anaesthetic eyedrops are instilled, the central corneal epithelium is removed and the surface of the eye is soaked in Riboflavin (Vitamin B2) eyedrops for half an hour. The cornea is then exposed to a specially calibrated ultraviolet light for half an hour, with regular checks to ensure the cornea is not becoming too thin. A bandage contact lens is placed and left on for several days while the eye heals. Antibiotic and anti-inflammatory eyedrops are used for up to 4 weeks and painkillers are prescribed for use as necessary in the first 2-3 days. About 5 follow-up visits are required in the 3 months following the treatment.
Need more information?
Contact Eye Doctors
Southern Cross Affiliated provider benefit to Keratoconus Patients
- no need for prior approval
- Southern Cross pays Eye Doctors directly