Corneal Cross Linking

In a normal eye the cornea (clear window at the front of the eye) has the strength to keep a regular curve shape. This curvature of the cornea helps to focus the image on the light sensitive layer (retina) at the back of the eye.

In keratoconus the cornea can become weak, thin and irregularly shaped. Instead of keeping its normal round shape, corneas with keratoconus can bulge forward into the shape of a cone. This leads to a blurred image on the retina and the need for glasses or contact lenses to sharpen it.

Normal corneas have crosslinks between its collagen fibres that keep it strong and able to retain its normal shape. In keratoconus, the cornea is weak with too few crosslinks or support beams. This weakened structure allows the cornea to bulge outwards.

The cross-linking procedure adds cross links or ‘cross beams” to the cornea, making it more stable and preventing further progression of keratoconus. These new crosslinks help strengthen the cornea which stops the thinning process and further loss of vision.  The aim of corneal cross-linking is to reach a period of stability before the condition has had a chance to progress to the advanced stages of requiring a corneal transplant.

Are there alternatives to Corneal Cross-Linking?

The current answer is no. Cross-linking is the only treatment that has been shown to stop the progression of keratoconus in more than 90% of cases. The procedure has been used for 20 years. Corneal transplant is the other option that is usually reserved for advanced cases where the vision has reduced considerably. Corneal transplant involves removing the diseased corneal tissue and replacing it with a donor cornea.

Who are the best candidates for Corneal Cross-Linking surgery?

Corneal cross-linking is most effective it it can be performed before the cornea has become too irregular  and thin in shape or there is significant vision loss from keratoconus or other causes of corneal disease. If done early, corneal cross-linking will stabilise or even improve the shape of the cornea. Patients must be at least 12 years old. Keratoconus often runs in families so it’s important for all family members of patients to be screened for keratoconus. Keratoconus tends to stabilise after 30 to 40 years of age but by then the glasses or contact lens prescription has become quite complex and a corneal transplant may be necessary to improve vision.

What happens at the pre-assessment?

In a pre-assessment, your ophthalmologist will measure the thickness of your cornea and make sure you are a good candidate for the procedure. You will have a routine eye exam to assess your visual acuity and general eye health. Your doctor will perform mapping of your cornea (called corneal topography) to determine the level of your eye condition. They will discuss your condition and all treatment options with you.

What to expect during the Corneal Cross-Linking surgery

Bring your normal glasses and/or a pair of sunglasses to the appointment to wear on the way home as you may have increased sensitivity to light.

The cross-linking treatment is done as an outpatient procedure at Bowen Eye Clinic. The surgeon will put numbing eye drops (anaesthetic drops) on your eyes so you won’t feel anything during the procedure. You will lie flat on your back on a bed and look up at a soft blue light during the treatment. The epithelium, a thin layer of clear protective cells (like skin) that covers the cornea is gently removed exposing the layer of the cornea to be treated for the cross-linking procedure. Next the surgeon will put riboflavin (vitamin B2) eye drops onto your eye for 30 minutes and you will be asked to look at a blue (ultraviolet) light for a further 10 minutes. The riboflavin together with the measured dosage of UV light encourages bonds between collagen fibrils to form, strengthening your cornea.

After the treatment, a contact lens bandage will be placed on your eye to help with healing and to make your eye more comfortable. You’ll need to keep this is place for a week until your follow up appointment, and you’ll be given eye drops to use. Any discomfort during healing is usually mild, and should only last the first few days

What to expect after the surgery

After your surgery you will be given antibiotic  and steroid drops, and artificial tear drops. The procedure should not be painful but the eye will become sore afterwards and this will last for a few days.

The antibiotic and steroid eye drops are stopped in approximately one week but the artificial tear drops will need to be continued for a while longer.

There will be a contact lens bandage in your eye for about one week to help the eye settle and be more comfortable. If your contact lens bandage falls out, throw it away. Do not put it back in again.

Your surgeon will see you at a follow up appointment in one week and will advise when to come for further follow-up checks as your healing progresses.

Do not get any non-sterile water in the eye until the healing process has been completed.

Take care washing your face, hair and showering.

Do not go swimming as this will risk an infection in the eye.

Remember to use your eye drops as recommended and do not rub your eye.

If your vision drops dramatically or there is significant pain or discharge please contact the clinic immediately.

You will require at least one - two weeks off work after the surgery. Please ask your doctor for a medical certificate if you require one.

Are there any risks in having the Corneal Cross-Linking?

The procedure is relatively simple and highly effective. It’s also very safe, and complications are extremely unlikely. As with any other surgical procedure, there are risks. Because corneal cross-linking includes the removal of the corneal epithelium (the thin layer on the cornea’s surface) risks may include infection or inflammation. Your doctor will discuss any other risks with you at your pre-assessment.

Will Corneal Cross-Linking prevent my needing a corneal transplant in the future?

Corneal cross-linking reduces the need for a corneal transplant in the future. About 10% of people who have had corneal cross-linking may still progress and could require a corneal transplant. A corneal transplant performed on a patient who has had corneal cross-linking may be more successful because the cross-linking treatment may have strengthened the patient’s cornea to better receive a transplant. Without corneal cross-linking treatment, at least 20% of all patients with keratoconus will eventually require a corneal transplant.

Will I need new glasses or contact lenses after Corneal Cross-Linking?

Because cross-linking sometimes improves vision, patients may find that their old glasses or contact lenses are too strong for them and they need to be assessed for new glasses or contacts. Most of the time people can wear their old glasses until several months after the procedure and then their optometrist can prescribe new ones.

Can I have Laser Eye Surgery after Corneal Cross-Linking?

Laser Eye Surgery is not recommended for patients who have keratoconus as it can make their condition and vision worse. All patients assessed for laser eye surgery are checked with corneal topography for early signs of keratoconus. Corneal cross-linking can however be used to treat post LASIK ectasia. Post LASIK ectasia is a recognised complication of laser eye surgery but with modern screening techniques is now very rare.

Will my vision be better after Corneal Cross-Linking?

It is important to remember that the procedure is to stop the progression of keratoconus.

Most patients find that immediately after the cross-linking treatment their vision is actually worse than it was before the treatment. This will be for about three to six weeks. Some people start to notice positive effects around four to eight weeks after the procedure. Any improvement in vision is considered a ‘bonus’.

 

Contact Bowen Eye Clinic on 0800 69 2020 to learn more about your keratoconus and whether corneal cross-linking is the right treatment for you.