Corneal cross-linking (also known CXL) is a treatment to prevent keratoconus getting worse. It successfully prevents worsening of your keratoconus in more than 90% of cases.
Keratoconus gets worse due to the shape of cornea becoming more like a cone. Your eye doctor may use the term “progression of your keratoconus”. This happens due to cornea being too flexible. CXL aims to make the cornea stiffer and prevent any further shape change. If the cornea is allowed to change shape, progressive sight loss can occur. In time, glasses may stop giving you clear vision and you would need to wear rigid contact lenses. Without treatment, the shape of the cornea can continue to worsen meaning patient would eventually need a corneal transplant. By performing CXL at the correct time, the treatment could make corneal transplantation for keratoconus obsolete.
Am I suitable for CXL?
Once a diagnosis of keratoconus is confirmed, regular corneal curvature scans will be taken to monitor your condition. CXL is recommended to patients whose keratoconus is getting worse or who are at a particularly high risk of progressive keratoconus. Your eye doctor will consider your spectacle prescription, your corneal topography (a special map taken of the front of your eye), your vision and also your age when making the decision to offer CXL. As natural cross-linking occurs with age, CXL would not be routinely offered to patients in their mid-thirties onwards. CXL is generally not needed in patients over the age of 40 as natural cross-linking occurs with age which makes keratoconus much less likely to progress in older patients. CXL is also used to treat post-LASIK ectasia.
How does CXL work?
The cornea is made up of layers of collagen fibres held together by cross-links. The photochemical reaction between the vitamin B2 drops and UV light increases the cross-links between collagen fibres in the cornea, thereby strengthening the cornea.
How is CXL performed?
CXL is performed at the Manningham Day Procedure Centre. The procedure is performed under local anaesthetic and takes approximately 30 minutes per eye.
During the procedure, you will lie comfortably on a bed. Anaesthetic eye drops are used to numb the surface of your eye and your eyelid will be held open with an eyelid speculum. The surface cells of the cornea (the epithelium) are first gently removed and the cornea is then soaked in Vitamin B2 (riboflavin) drops. Following this, UV light is shone on the cornea to activate the riboflavin. At the end of the procedure a protective bandage contact lens is placed over the cornea for 5-7 days for comfort and to support the regeneration of new epithelial cells.
What is the evidence for CXL?
Studies have shown that CXL increases corneal strength by up to 300% and is successful in stopping progression of keratoconus in over 90% of patients. It is currently the only treatment available to stop keratoconus from worsening. Without CXL, 20% of patients with keratoconus will eventually require a corneal transplant to restore vision; however, with this treatment, this figure has dropped to 3%.
Will my vision improve after CXL?
The aim of CXL is to stabilize keratoconus. This treatment alone does not attempt to improve vision. After treatment, you will still need to wear your glasses and/or contact lenses.
However, CXL combined with laser resurfacing, known as laser refractive CXL, is a treatment option that can improve the overall shape of your cornea at the same time, resulting in reduced spectacle prescription and improved spectacle corrected vision. Patients with early keratoconus may even find that their vision improves enough such that they are much less dependent on glasses and contact lenses. This is a relatively new treatment that has shown impressive results in a select group of patients who meet the strict treatment criteria.
What is the recovery like after CXL?
At the end of the procedure, your vision will be quite blurry. We recommend that you have someone to drive you home. However, if this is not possible, we recommended that you take a taxi door-to-door.
Your eyes will be sore, watery and light sensitive for the first 3-5 days as the epithelium re-grows and the surface heals. Vision is blurred during this healing phase and usually recovers within 1 week although it continues to improve for several weeks after CXL. Most people are able to go back to work and resume normal activities a week after CXL.
You will be given antibiotic and anti-inflammatory drops to prevent infection and assist with healing. You will have an appointment 5-7 days after the procedure to have the bandage contact lens removed and thereafter as advised by your corneal specialist.
Can there be any complications or risks?
As with any surgical treatment, there are possible complications and risks that must be considered carefully. CXL is generally a safe procedure.
The complications and risks will be discussed with you at your clinic appointment. You will be asked to sign a consent form. The complications/risks listed on the consent form will include:
Infection of the cornea
Scarring of the cornea
Haze of the cornea
Delayed healing of the surface of your eye
Failure of CXL and the need for a further CXL treatment
Causing an irregular corneal surface
Temporary or permanent loss of vision
Need for corneal transplantation