Corneal Cross-Linking

What is Corneal Cross-Linking?

The cornea is made up of layers of protein fibres called collagen. In keratoconus and other conditions of the cornea, there is a progressive weakening of these collagen fibres that allows the cornea to deform. In keratoconus, this weakening results in irregularities in the corneal surface causing it to change it shape, which in turn causes the vision to deteriorate.

Corneal Collagen Cross-linking (or CXL) is a treatment that strengthens the cornea by forming cross-links or bonds between the collagen. This causes the cornea to become stiffer and resist further deformation and vision loss. Cross linking is recommended to prevent further deterioration in people with worsening keratoconus. Although cross-linking aims to stabilise your vision, some patients may notice a slight improvement in their vision. Glasses or contact lens will still be required for good vision.

Collagen cross-linking can also be used to treat other conditions with weakened corneas such as post-LASIK ectasia and pellucid marginal degeneration.

Cross linking uses ultraviolet light and vitamin B to strengthen the cornea: the cornea is soaked with vitamin B drops that coat the collagen fibres, after which ultraviolet light is beamed on the cornea to form links between vitamin B molecules and bind the fibres.

How does cross-linking treat Keratoconus?

The first part of this procedure gently removes the surface layer of the eye (epithelium). This can be performed manually or by a highly accurate laser. The laser procedure is called phototherapeutic keratectomy (or PTK). The benefit of this method is that the laser can also be used to smooth some of the irregularities, resulting in sharper vision.

If only PTK is performed, any improvement in vision could be lost if the keratoconus continues to develop. Therefore, corneal cross-linking is carried out immediately after the laser. This strengthens the cornea and makes the new corneal shape permanent.

If suitable for this procedure, patients may have a reduction in their glasses prescription, but the combined laser crosslinking procedure aims to improve the quality of vision in glasses. It may be possible to remove the need for glasses completely, but this typically requires a further procedure, such as implantable contact lenses.

Cross-linking is performed as a day procedure with local anaesthetic eye drops. These numb the eye and gently remove the outside skin surface of the cornea, which is necessary for the vitamin B molecules to penetrate the cornea effectively. Ultraviolet light is used for typically 10 minutes to complete the cross-linking. Both eyes can be treated at the same time. After the procedure, a soft bandage contact lens is placed to help with healing and discomfort.

Where will I have collagen cross-linking CXL surgery?

I perform all my surgical procedures at Vision Care Clinic.

How long is the recovery after collagen cross-linking surgery?

The bandage contact lens will be removed after 4 to 7 days. The eye will feel gritty and uncomfortable, especially for the first 48-72 hours. These symptoms will improve over the next week. You will be provided with analgesics to help the discomfort. You may also find ice packs helpful, especially when you return following the procedure.

Vision will initially be blurred. It will be at its worst on days 5-7 after the surgery and then slowly improve. Typically, you will regain >80% of your vision after two weeks, with the remaining settling over the coming weeks. It is normal for vision to vary during this period. You will find lubricants helpful. You may need to change your glasses or contact lenses after a few weeks.