Corneal Collagen Cross-linking
What is Corneal Collagen Cross-linking?
The human cornea is a clear window at the front of the eye, which is responsible for focusing light onto the retina. It is essential for the cornea to maintain its natural round doom shape. In keratoconus, the diseased cornea begins to bulges into a cone-like shape (like a lemon) and at the same time it becomes significantly thinner. As a result, vision is significantly impaired.
Corneal Collagen Cross-linking is a photochemical procedure which is used to strength the cornea in people with structural corneal disorders, such as keratoconus. The cross-linking treatment is thought to work by forming new “bonds” within the central portion of cornea (stroma), which act as stabilizers or anchors. It has been shown to stop or slow the bulging process seen in keratoconus.
The procedure is relatively simple and highly effective. It’s also very safe, and complications are extremely unlikely.
How is Corneal Collagen Cross-linking performed?
The primary aim of this procedure is to allow eye drops that are rich in vitamin B2 (riboflavin) to diffuse into the cornea. This one-time, in-office procedure involves several steps. Your ophthalmologist will:
- Numb your eye with anaesthetic eye drops
- Gently remove the outer layer of your cornea
- Instil special vitamin drops (riboflavin) in your eye many times over 30 minutes
- Shine a special ultraviolet light on your eye for another 30 minutes and keep adding drops
- Insert a bandage contact lens and patch your eye at the end of the treatment
The vitamin drops and ultraviolet light work together to make collagen bonds in the cornea stronger, allowing it to become stiffer and usually stop bulging out.
Who are the best candidates for Corneal Collagen Cross-linking?
Patients with the following corneal disorders will benefit from Corneal Collagen Cross-linking:
- Progressive Keratoconus
- Other corneal ectasias such as Pellucid Marginal Degeneration
- Corneal ectasia following refractive surgery or radial keratotomy
- Certain corneal infections
It is important to understand that corneal collagen cross-linking is not a cure for the above corneal diseases. Instead, it aims to slow or even halt the progression of these conditions. Also, it is not a treatment for every patient with structural problems of their corneas. This treatment is not suitable for patients who have:
- Previous Herpes infection of their corneas
- Corneal thickness less than 400 micrometres.
Your ophthalmologist will evaluate your condition before discussing the best treatment options for you.
What should I expect after Corneal Collagen Cross-linking?
- You should arrange to have someone take you home on the day of the treatment, and to the post-treatment appointment the following day.
- Do not plan to drive for approximately one week after treatment
- You will not be able to go swimming for a month and it is recommended no water exposure in the first week after treatment.
- You should minimise sun exposure in the first month after surgery
After the treatment, it will continue to be necessary to wear spectacles or contact lenses (although a change in the prescription may be required). However, the treatment will help prevent further deterioration in the condition and the need for corneal transplantation.
As mentioned, Corneal Collagen Cross-linking can stop keratoconus from worsening. It can also help flatten the central cornea in about half of the patients, who often experience better vision as a result, although this beneficial effect is not always predictable.
The full effect of Corneal Collagen Cross-linking may take 6 months or longer to settle, and not all patients with keratoconus are suitable to undergo this procedure.
What are the risks associated with Corneal Collagen Cross-linking?
Although Corneal Collagen Cross-linking is a relatively safe procedure with great clinical benefits, there are some potential risks associated with the procedure:
- Delayed re-epithelialization (healing of surface layer)
- Treatment failure
- Endothelial decompensation
- Progressive corneal thinning from melting or inflammation
Your ophthalmologist should be able to explain the individual risks and possible side effects to you and decide whether this treatment is the right option for you.