Corneal Cross-Linking (CXL) - Diagnosis and Treatment

What is Corneal Collagen Cross-Linking?

Corneal collagen cross-linking (CXL) is a technique that was first used in 1998 to treat patients with a disease called keratoconus. In keratoconus , the cornea (the front clear window of the eye) becomes weak, thin and irregularly shaped. CXL is now being performed for patients with this condition in approximately 400 centers throughout the world. Through a research study, ClearView Eye and Laser Medical Center is now able to provide this investigational treatment to our patients.

XL works by adding "crossbeams" between the weak layers of the cornea in keratoconus eyes

What does Corneal Collagen Cross-Linking do?

Corneal collagen cross-linking strengthens the cornea by allowing it to re-form new cross-links between the collagen fibers. These new cross-links help strengthen the cornea which stops the thinning process and further loss of vision.

How effective is Corneal Collagen Cross-Linking?

Many research studies have shown that CXL prevents further vision loss in over 95 percent of patients, with 60-70 percent of patients having improved vision. 1,2,3,4,5

How long does Corneal Collagen Cross-Linking treatment last?

Based on more than a decade of CXL study results, the beneficial effects of CXL appear to be long lasting and there is evidence that this strengthening effect will be permanent. 2

Is Corneal Collagen Cross-Linking new?

Corneal collagen cross-linking has been performed since 1998. The results and safety profile of CXL have been excellent in numerous studies throughout the world 1. The CXL procedure is now routinely performed on patients as young as 10 years old in Europe to prevent the development of keratoconus.

What is keratoconus?

Keratoconus is a common disease which occurs in between 1 in 500 and 1 in 1,000 Americans. In this condition, the cornea becomes weak, progressively thins and irregular in shape, producing high levels of astigmatism. This can interfere with the ability to see clearly. Often keratoconus patients first require glasses, then contact lenses, and if the condition progresses to a severe level, a corneal transplant may be required.

Can Corneal Collagen Cross-Linking prevent the need for corneal transplant?

Many studies have shown that CXL can often prevent the need for a corneal transplant and allow patients to wear contact lenses or glasses more comfortably and safely again.1,2,3,4,5

Is Corneal Collagen Cross-Linking like LASIK?

No. LASIK is a procedure that reduces or, in some cases, may even eliminate the need for glasses or contact lenses by removing corneal tissue. The CXL treatment does not remove tissue. The purpose of CXL is to prevent further deterioration of vision for most patients and to potentially improve vision. Patients will typically require a lower eyeglass prescription and can have an easier time being fit for contact lenses.

Can a corneal transplant be done after Corneal Collagen Cross-Linking?

If CXL does not prevent the need for a corneal transplant, then a corneal transplant generally can be performed.

Does Corneal Collagen Cross-Linking need to be repeated?

In many studies, the vast majority of patients respond to a single CXL treatment and do not need to have the procedure repeated. For the occasional patient in whom this treatment is not successful, CXL can often be repeated.

Does insurance cover Corneal Collagen Cross-Linking treatment?

Unfortunately, we have yet to see an insurance policy that does cover this treatment.

Is financing available?

Convenient, affordable financing is available to help our patients get the treatment they need before their keratoconus or other similar condition progresses to the point where they can no longer have CXL.

Can Corneal Collagen Cross-Linking be performed for everyone with keratoconus?

To qualify for the CXL study, patients must be at least 18 years old and their corneas cannot be too thinned or too scarred for the procedure. During your consultation, we will determine if CXL might be a good treatment option. ClearView Eye and Laser Medical Center offers a five-minute no-touch screening test to determine whether CXL can potentially be of benefit.

Should your relatives be tested?

As you may know, keratoconus is a condition that often runs in families, so it's important to arrange a screening for all family members of patients with keratoconus.  If caught early, there is a good chance that CXL can halt the progression of keratoconus and prevent the need for a corneal transplant and/or uncomfortable contact lens wear for many patients.

How is Corneal Collagen Cross-Linking performed?

The CXL treatment is an outpatient procedure performed in Dr. Feldman's office. You will need to lie flat on your back in a reclining chair and look up during the treatment. In order to prevent you from blinking, an eyelid retainer will be placed between your upper and lower eyelids. The cornea is then prepared by removing the epithelium, a thin layer of clear, protective skin that covers the cornea. Next, vitamin (riboflavin) eye drops are placed in the eye, one drop every two minutes for 30 minutes. The treatment is concluded with another set of vitamin (riboflavin) eye drops instilled every 2-5 minutes for 30 minutes while looking at a special blue (ultraviolet) light.6

How long does the whole procedure take?

If two eyes are being treated at once, the procedure takes approximately 30 minutes. If only one eye is being treated at a time, the procedure takes approximately one hour.

Does the Corneal Collagen Cross-Linking procedure hurt?

No. Anesthetic eye drops are used to avoid any discomfort during the procedure.

What are the potential risks of Corneal Collagen Cross-Linking?

Although this procedure has been used for more than 10 years, there may still be some risks or side-effects that are not known yet. The most common side effects of epithelial (outer layer of the eye) removal include moderate pain, and blurred vision that typically lasts up to five days. There is also risk of infection, corneal inflammation, corneal haze, dry eye and delays in epithelial healing.

The most common side effects from using riboflavin drops are blurred vision and mild redness or stinging in your eyes. Uncommon side effects can include difficulty breathing, wheezing, a sudden drop in blood pressure, a fast pulse, sweating or swelling around the mouth, throat or eyes. The most common side effects of the UV-X light source include blurred vision, mild redness or stinging in the eyes. Another side effect of the UV-X light source is if too much UV light is absorbed, eye structures such as the cornea, the lens and the retina can be damaged. This can lead to temporary loss of vision for 24-48 hours. It may also lead to additional surgery.

An uncommon side effect may be changes to other layers of your cornea. The most common side effects of topical antibiotics include: ocular irritation (pain, swelling, burning, dry or itchiness of the eye). There may be side effects or discomfort from the medications that are not yet known. Although rare, a serious infection or inflammation can lead to permanent loss of vision, or even loss of the eye. Additional surgery, although rare, may be needed.

Can I have one eye treated at a time?

Yes, your doctor will discuss with you the advantages and disadvantages of treating one eye or two eyes at a time.

Can I have Corneal Collagen Cross-Linking if I already had a corneal transplant?

Each patient and each patient's eyes are different.  In some cases CXL can be performed after corneal transplantation.

If Corneal Collagen Cross-Linking works for me and stops my vision from getting worse, can I have laser vision correction afterwards?

Some patients may be able to have an excimer laser treatment (PRK) to improve their vision without the need for glasses after they have healed from the CXL procedure.

Do I have to stop wearing contacts before having Corneal Collagen Cross-Linking?

If you wear soft contact lenses it is recommended that you do not wear them for about three days before the procedure. Patients wearing hard or combination lenses, such as SoftPerm or soft toric contacts, are recommended to remove their lenses for approximately 10 days prior to the CXL procedure.

When can I resume wearing contact lenses?

Most patients can return to wearing contact lenses one to two weeks after having the cross-linking procedure.

Will I need new glasses or contacts after Corneal Collagen Cross-Linking?

Because cross-linking often improves vision, patients usually find that their old contacts or glasses may no longer work and they need to be refit with new, glasses and/or contact lenses.

When will I notice any improvement in my vision after Corneal Collagen Cross-Linking?

Most patients find that for the first few days after the cross-linking treatment, their vision is actually worse than it was before the procedure.  This usually goes on for roughly 2-4 weeks.  Many patients start to notice positive effects 2-3 weeks after the procedure and major improvement in vision generally takes 4-6 months.  In some studies, five years after cross-linking, patient's vision and astigmatism are still continuing to improve.2

What is astigmatism?

Astigmatism simply means that the front surface of the eye (the cornea or clear window in front of the eye) is shaped more like a football than like a basketball.

What do ladders and Keratoconus have in common?

In keratoconus, the cornea has weakened structural support; fewer cross-links or support beams. This weakened structure allows the cornea to bulge outwards. The cross-linking procedure adds ladder rungs or cross-links to the cornea, making it more stable.

For more information about keratoconus, and/or our diagnostic screenings and treatments, please call Clearview Eye and Laser Medical Center.

  • 1. Wollensak G, Spoerl E, Seiler T.; Riboflavin/ultraviolet-a-induced collagen cross-linking for the treatment of keratoconus.  AJO 2003 May;135(5):620-7.
  • 2. Raiskup-Wolf F, Hoyer A, Spoerl E, Pillunat LE.;  Collagen cross-linking with riboflavin and ultraviolet-A light in keratoconus: long-term results. J Cataract Refract Surg. 2008 May;34(5):796-801.
  • 3. Coskunseven E, Jankov MR 2nd, Hafezi F.; Contralateral eye study of corneal collagen cross-linking with riboflavin and UVA irradiation in patients with keratoconus.
    J Refract Surg. 2009 Apr;25(4):371-376
  • 4. Grewal DS, Brar GS, Jain R, Sood V, Singla M, Grewal SP.; Corneal collagen cross-linking using riboflavin and ultraviolet-A light for keratoconus: one-year analysis using Scheimpflug imaging. J Cataract Refract Surg. 2009 Mar;35(3):425-32.
  • 5. Spoerl E, Mrochen M, Sliney D, Trokel S, Seiler T.; Safety of UVA-riboflavin cross-linking of the cornea. Cornea. 2007 May;26(4):385-9.
  • 6.Trattler W, Rubinfeld R, Corneal Collagen Cross-linking; Cataract and Refractive Surgery Today; September 2009

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