Corneal Collagen Cross-Linking: A Treatment Option For Keratoconus

Corneal cross-linking (CXL) is an eye care procedure designed to strengthen and stabilize the cornea. The procedure is primarily used to treat and manage progressive keratoconus.

This minimally invasive procedure helps prevent further deterioration of vision and can delay or eliminate the need for corneal transplants.

Corneal cross-linking is a popular treatment for keratoconus. This eye condition occurs when the cornea thins and changes shape over time. As the cornea begins to thin, it bulges outward, resembling a cone.

This process can cause blurred vision and a range of other symptoms including:

• Glare and halos around lights.

• Difficulty seeing at night.

• Eye irritation or headaches associated with eye pain.

• Increased sensitivity to bright light.

• Sudden worsening or clouding of vision.

While keratoconus does not cause total blindness, it can lead to significant vision loss and may require patients to update their contact or glasses subscription.

Mild forms of keratoconus can typically be treated with glasses or contacts. Scleral contact lenses are a popular treatment for some patients. These rigid lenses hold the cornea in place and provide a regular front curvature of the eye to improve vision.

However, if symptoms are left untreated, significant vision loss can occur. For instance, progressive keratoconus can cause stretching to the point of needing a corneal transplant.

Corneal cross-linking is a surgery primarily used to treat keratoconus. The goal of the surgery is to strengthen the cornea and prevent it from bulging more. The procedure works by creating bonds between the collagen fibers in a patient’s eye. These bonds act as support that holds the cornea in place, keeping it stable.

While there are treatments for milder forms of keratoconus, corneal cross-linking is the recommended treatment for progressive keratoconus. Corneal cross-linking is a minimally invasive surgery that can stop the cornea from stretching and thinning. This often prevents the need for more invasive procedures such as a corneal transplant.

There are two types of cross-linking the doctor may perform: “epithelium-off” and “epithelium-on.”

Epithelium-off cross-linking: This is the standard version of the surgery. During the procedure, the surgeon will completely remove the epithelium (outer layer of the cornea). By removing this layer of the cornea, the surgeon can operate on riboflavin of the cornea more easily.

Epithelium-on cross-linking: In this version of the procedure the epithelium is left intact, rather than being completely removed. By doing this, patients may enjoy a faster recovery time and less discomfort. Epithelium-on cross-linking is a newer and more experimental version of the surgery. Experts are still unsure whether it is more effective.

The primary benefit of corneal cross-linking is that it slows keratoconus without the need for an invasive procedure. Some additional benefits that patient’s may experience are:

• Better corneal stability: The procedure strengthens the cornea and prevents further bulging.

• No need for corrective lenses: Patients may not need corrective lenses or glasses to improve their vision following surgery.
  

• Non-invasive treatment: surgery takes 60 to 90 minutes and is considered safe

While corneal cross-linking is typically used to treat keratoconus, it can also be used as a treatment for similar corneal conditions. For example, surgery can prevent corneal bulging (ectasia) that can take place after LASIK surgery.

During a typical LASIK procedure the surgeon will remove corneal tissue to correct blurry vision. In very rare cases this removal can weaken the cornea, creating a bulge similar to keratoconus—which can be treated with corneal cross-linking.

A corneal cross-linking surgery will typically begin with the doctor administering eye drops to numb the eyes. This is done to prevent pain when the surgeon removes the epithelium (thin outer layer of the cornea) at the start of surgery.

Next, the surgeon will apply vitamin B (riboflavin) eye drop medicine and use a device to shine UV light rays at the cornea. This light activates the riboflavin in the cornea and helps collagen fibers form.

Once the procedure is finished, a bandage contact lens will be placed over the patient’s eye. This is intended to help the cornea heal and is typically left in place for about a week. A patient’s ophthalmologist may also prescribe antibiotic and steroid drops to help the eye heal.

In the week after surgery patients will need to give their eye time to heal. During this time patients should make an effort to refrain from touching or rubbing their eyes, as this can stall the healing process.

Additionally, patients should avoid:

• Getting water in their eyes

• The use of eye makeup

• Participating in heavy exercise

• Spending time in smoky or dusty places with irritants that can affect their eyes

While corneal cross-linking is considered a safe and effective surgery, there are a few side effects patients may experience. These typically occur within the first few weeks following the procedure.

They can include:

• Foreign body sensation (feeling like there is something in the eye)

• Light sensitivity

• Dry eye

• Blurry or hazy vision

• Mild discomfort or eye pain

In some cases more serious side effects can occur. These are very rare, but may include:

• Worsening of keratoconus

• Scarring

• Infection

• Vision loss

If a patient experiences any of these symptoms in the weeks following surgery, they should immediately see their eye doctor for a follow up.

Most patients will enjoy a swift recovery and can begin to enjoy normal daily activities within one to two weeks post-surgery. However, it may take several months for vision to fully stabilize.

During the time it takes a patient's vision to stabilize they may need to wear glasses or contacts to correct vision. Typically six to eight weeks post-surgery, patient’s will have their glasses or contact lenses removed or refitted.

Patients should also realize that corneal cross-linking will not make their existing corneal bulge go back to normal. The surgery is meant to keep keratoconus from getting worse and prevent the need for more invasive procedures like a corneal transplant later on.