Before 1998, the only treatment options for keratoconus were custom contact lenses, Intacs and/or corneal transplants. Corneal transplantation is a major surgery performed in an operating room. It involves a doctor making incisions and replacing part of the cornea with corneal graft tissue secured by sutures. As a result, there is a lifelong risk of rejection of the corneal graft as well as the risk of wound rupture, which can lead to permanent loss of vision and, in some cases, loss of the eye
In 1998, doctors in Germany introduced Corneal Collagen Crosslinking with vitamin (riboflavin) eyedrops and UV light (CXL "epi-on") to treat patients with keratoconus. Today, doctors are performing CXL and successfully treating patients in over 400 centers outside the United States (including all 25 European Union nations since 2006). This treatment is not yet widely available in the U.S. because the Food and Drug Administration (FDA) has not approved the use of UV light and Riboflavin in this therapy. Through research studies coordinated by the CXLUSA Study Group and others, select participating centers are now able to provide this breakthrough treatment to qualified patients.
What Does CXL Do?
|Normal corneas have crosslinks within their collagen fibers that keep it strong and able to retain its normal shape. || |
| In keratoconus, the cornea is weak with insufficient structural support. || |
|This weakened structure allows the cornea to bulge outwards into
irregular shapes which can then cause poor vision, glare and difficulty
seeing well enough to drive at night and perform normal activities that
require good vision.
The crosslinking procedure can add strength to
the cornea, making it more stable so it can hold its shape and focusing
power. These “links” help strengthen the cornea, which stops the
thinning, bulging and further loss of vision. ||
Who Qualifies for CXL?
To qualify for CXL, patients must be at least 8 years old. To find out if CXL is right for you, visit a participating doctor for a complimentary, no-touch, painless screening. During your consultation, the doctor will determine if CXL might be an option for you. Find a doctor nearest you.
What is the CXL Procedure Like?
The CXL treatment is an outpatient procedure performed in the doctor’s office using only numbing eye drops and a mild sedative (generally a Valium tablet). Before the light is used, the epithelium, a thin layer of clear, protective tissue (like skin) that covers the cornea is prepared for the CXL procedure. Next, vitamin B2 eye drops (riboflavin) are used in the eye and the patient is asked to look at a special blue (ultraviolet) light while lying comfortably on the reclining chair. It’s generally easy for patients to look at this light because the eyes are numb and we use drops to keep the eyes moist. From a patient’s perspective, the UV light appears to have a soft blue color. See picture for patient's view of light.
Does the CXL Procedure Hurt?
No. The crosslinking procedure is painless. Anesthetic eye drops are used to avoid discomfort during the procedure. Some patients have discomfort after the procedure and your surgeon can tell you whether you are or are not likely to do so and how to ensure your comfort.
How Long Does the Procedure Take?
If two eyes are being treated at once, the procedure takes approximately an hour and a half. If only one eye is being treated at a time, the procedure takes approximately one hour.
Are There Different Technique Options?
In the least invasive CXL treatment called transepithelial (or epi-on) CXL technique, the surface skin layer (epithelium) of the cornea is not removed so the recovery is much faster than the traditional CXL technique. This least invasive technique can only be done on corneas that are thick enough. Your surgeon will be able to determine if you might be a candidate for this less invasive transepithelial (or epi-on) CXL treatment.
Intacs or corneal rings, along with other techniques, can be used to treat astigmatism in keratoconus patients, but they do not stop the progression of the disease. The only treatment that stops progressive vision loss in keratoconus or ectasia is CXL.
Recovery Time from the Procedure
We want to help you get back to your normal life activities as quickly as possible. Based on the treatments that are best you’re your eyes, your doctor can tell you when you can expect to return to your usual activities. With transepithelial (or epi-on) CXL, most people return to their usual activities the next day. With traditional epithelium off CXL, most people can do so after 5-8 days.
When can I resume wearing contact lenses after CXL?
This will depend on how difficult it is for you to see without your contacts, the type of CXL procedure you had, and how fast your eye heals. With transepithelial (or epi-on) CXL, can typically start wearing corrective contact lenses within a few days to a week. With traditional (epi-off, more invasive) CXL, most patients return to wearing contact lenses 2 to 6 weeks after the procedure. Your surgeon will determine how long this might take in your case.
When will I notice improvement in my vision after CXL?
The main purpose of CXL is to prevent further vision loss as it is a mainly preventive treatment. Some patients also get some improvement in their vision as well. Generally, with CXL, visual improvement is a long process. With the less invasive, transepithelial CXL, some patients have found their vision improved somewhat as early as several weeks after treatment. With the traditional (more invasive epi-off) CXL procedure, most patients find that immediately after the cross-linking treatment, their vision is actually worse than it was before the procedure. This usually goes on for roughly 3-6 weeks. Patients may start to notice positive effects 4-8 weeks after the procedure and may experience major improvement in vision at least 3-6 months after the procedure. In some studies, patients’ vision and astigmatism were still continuing to improve five years after the crosslinking procedure.
Long Term Results
Improvement in corneal shape and vision can continue over many years, with some patients noticing further improvement in their quality of vision even 2 to 4 years following the treatment.
Can I Have One Eye Treated at a Time?
Yes, your doctor will discuss the advantages and disadvantages of treating one eye or two eyes at a time.
Who Performs the Procedure?
Today, doctors are performing CXL and successfully treating patients in over 400 centers outside the United States. It is not yet widely available in the U.S. because the Food and Drug Administration (FDA) has not specifically approved the use of UV light and Riboflavin in the therapy. However, through a research study coordinated by the CXLUSA Study Group and others, select select participating doctors are now able to provide this breakthrough treatment to qualified patients. Find a participating doctor or study center here.
How Effective is CXL?
Many research studies have shown that CXL may prevent further vision loss in over 98% of patients and improves vision in over 50% of patients treated.
When is the Best Time to Have CXL?
As with most conditions, prevention of a problem is better than treatment of a problem. The best time to treat keratoconus is before the effects become apparent and vision has been lost. However, this does not mean that people with very poor vision from keratoconus cannot be helped by CXL. The best way to know if you CXL can help you, would be to visit a practicing doctor for a screening. Find a doctor nearest you.
How Long Does the Effect of CXL Treatment Last?
Based on CXL study results over more than a decade, the beneficial effects of CXL appear to last for many years and there is some evidence that the strengthening effect may be permanent.
Does CXL Need to Be Repeated?
In many studies, the majority of patients responded to a single vitamin and light CXL treatment and did not need to have the procedure repeated. CXL can be repeated if the first treatment is not effective.
CXL and Corneal Transplants
Can CXL prevent the need for corneal transplants?
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.
What’s the difference between a corneal transplant and CXL?
Corneal transplantation is a major surgery performed in an operating room. It involves a doctor making incisions and replacing part of the cornea with corneal graft tissue secured by sutures. As a result, there is a lifelong risk of rejection of the corneal graft as well as the risk of wound rupture, which can lead to permanent loss of vision and, in some cases, loss of the eye.
Can a corneal transplant be done after CXL?
If CXL does not prevent the need for a corneal transplant, then a corneal transplant can generally be performed. It is possible that CXL, by strengthening the peripheral parts of the cornea, can make a corneal transplant even more successful if a transplant ever does become necessary.
Can I have CXL if I have already had a corneal transplant?
Each patient and each patient’s eyes are different. In some cases CXL can be performed after corneal transplantation. The best way to know if you qualify for CXL, would be to visit a CXL specialist doctor for a screening. Find a doctor nearest you.
CXL and Vision Correction Options
If CXL works for me and stops my vision from getting worse, can I have laser vision correction or Intacs afterwards?
Some patients may be able to have an excimer laser treatment (topo-guided PRK) or Intacs to improve their vision without glasses after they have healed from the CXL procedure. Although every case is different, we usually recommend waiting at least a year after CXL to consider a laser or other procedure to further improve your vision. Sometimes we can perform other vision correction procedures roughly around the same time as CXL. Each case is different and your expert CXL surgeon can help you learn which procedure(s) are best for you.
Do I have to stop wearing contacts before having CXL?
This can vary based on how difficult it is for you to see without your contacts. In order to obtain the most accurate measurements of your corneal astigmatism (distortion of the cornea) it is recommended that soft contact lenses not be worn for five days before, and hard contact lenses for two weeks before. However, patients whose vision is unacceptable without contact lenses can wear them until the day of procedure.
Will I need new glasses or contacts after CXL?
Most of the time, patients can wear their old eyeglasses after CXL until several weeks or months after the procedure when their doctor will consider prescribing new ones. The effects of CXL differ from patient to patient and your doctor can help in advising you when to change contacts or glasses. Because cross-linking can improve vision over months and years, patients often find that their old contacts or glasses are too strong for them and they need to be refit with new glasses and/or contact lenses.
Is CXL 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 somewhat improve vision. Patients will typically require a lower eyeglass prescription or can have an easier time being fit with contact lenses. Remember, CXL is very good for preventing further vision loss from keratoconus but is generally not a treatment that markedly improves vision like LASIK does.
Paying for CXL
Does insurance cover CXL treatment?
No. Investigational procedures are not covered by medical insurance.
Cost of Being in the Study
There is a cost for undergoing cross-linking, which includes the many tests that need to be performed before and after your procedure to determine the changes in your vision and corneal shape over time. Financing is available to help patients cover the cost of CXL. To find out more about cost, ask a doctor or staff. Find a doctor nearest you.