Corneal Collagen Cross-Linking (CXL)

Corneal cross-linking (CXL) is a treatment for patients with keratoconus or post-LASIK ectasia (bulging of the cornea after LASIK surgery), which can prevent their condition from getting worse. It is successful in over 90% of cases. Although approved and used in Europe since 2003, it was not FDA approved in the US until April 2016.

After treatment, you will still need to wear eyeglasses or contact lenses. Your eye will be sore for about 1 week after the procedure. Although vision is often hazy at first, most patients can resume contact lens wear and return to work after one week. As with all procedures, there are risks; CXL is safe, but that is a small chance (less than 2%) of worse vision afterwards.

Normal Cornea vs Cornea with KeratoconusKeratoconus gets worse because the cornea weakens. CXL uses UV light and vitamin B2 (riboflavin) drops to stiffen the cornea. Used together, they cause fibers within the cornea to cross-link (bond) more tightly. This treatment mimics normal age-related stiffening of the cornea, which is known as “natural cross-linking”.

CXL is recommended for patients who show worsening of their keratoconus or ectasia; or for those who wish to undergo laser eye surgery but are at increased risk for ectasia post-operatively (for example, those who have very thin corneas, have suspicion for keratoconus, or those who are post-RK surgery). Because of natural cross-linking with age, keratoconus usually stops getting worse by mid-40’s, so CXL is not usually required for older patients (although each case is treated on an individual basis).

CXL is the only treatment currently available that can stop keratoconus and ectasia from getting worse. Evidence from multiple studies one-year post-CXL showed success in halting disease progression in more than 90% of eyes—with more than 45% of eyes also gaining an improvement in corneal shape. Long-term studies (5+ years) also suggest a similarly high success rate in preventing keratoconus progression. Vision is better after CXL in about 50% of eyes treated.

If you need CXL for both eyes, we can offer you treatment for both eyes at the same time. CXL is performed as a ‘same-day procedure’, meaning that you come to the office or surgery center, have the procedure and go home the same day. There is usually no need for anesthesia or an IV, but if you are nervous we can give you some medicine by mouth to relax you.

Procedure Overview


The procedure typically lasts 2-4 hours, depending on the case. This is mainly because riboflavin eye drops are applied to your eye for about 45 minutes prior to UV light treatment. Depending on the technique your doctor uses, UV light may be applied for 15-30 minutes. Anesthetic eye drops are given during the course of the CXL procedure so that you are comfortable and a small surgical clip is placed to keep your eyelids open. The surface skin of your eye (‘epithelium’) is gently brushed clear before the installation of riboflavin drops. Following application of riboflavin drops, your doctor will check your eye(s) to ensure there has been good absorption of the riboflavin. Following this, UV light is shone at your eye for a predetermined amount of time (15-30 minutes). Then, a soft bandage contact lens (a thinner, larger version of a regular contact lens) is placed on your eye.

After CXL

You will be given eye drops to use after CXL. The soft bandage contact lens will remain in your eye until the surface has healed (about 4-7 days). If the bandage lens falls out during this time, please throw it away—do not attempt to reinsert it.

The anesthetic drops will wear off later on the day of your procedure. Your eye will then become gritty, red, uncomfortable and sensitive to light for several days. Everyone’s experience of pain is different—some patients report very little discomfort—others describe the first few days as very painful. Because your eyes may be sensitive, many patients find sunglasses helpful.

Your vision will be quite blurry at first but will clear gradually over the first few weeks. It is normal to experience fluctuating pain and vision within the first few days of CXL. However, if you experience increasing pain 3-4 days after the procedure, this could mean there is an infection and you should visit your eye doctor’s office as soon as possible. Please note, the infection rate is rare following CXL, affecting less than 1% of patients.

Applying Eye DropsYou should allow at least 4-7 days off work/studies while the surface of your eye heals from CXL. You will be placing eye drops in your eyes at least 4 times per day for the first few weeks. Day-to-day activities, such as watching TV or using a computer will not do any damage to your eye, but you may find it more comfortable to rest with your eyes closed early on. You will be given an appointment the day after CXL and then usually 5-7 days later to check that your eye is healing properly. Some patients need to be seen every day post-CXL, to ensure the surface of the eye is healing well.

It is important to put the eye drops in your eye(s) as prescribed. Wash and shower normally, but try not to get water in your eye(s). You may exercise 2-3 days after CXL, but you should not swim, use a hot tub or garden for 7-10 days after CXL.

Your eye doctor will check your vision in the office after CXL to confirm if it is good enough to drive. It is usually safe to resume contact lens wear once the eye surface skin layer has healed—this is usually the second week after CXL. Therefore, you should have someone accompany you (or have a form of transportation) for the day of CXL, and all follow-up visits until you have been ‘OK-d’ by your doctor to drive.

Risks of CXL

In general, CXL is very safe, but like all surgeries, your eye needs time to heal and problems do occasionally occur. Approximately 2% of patients will lose some vision in the treated eye as a result of haze, scarring, and corneal surface shape irregularity. In most cases, this vision loss is potentially reversible with medication or a surgical procedure (laser or corneal transplant). Without CXL treatment, at least 20% of all patients with keratoconus will eventually require a corneal transplant. The risk of transplant for patients with documented disease progression is much higher.

Is Corneal collagen cross-linking right for you?

Corneal collagen cross-linking is a treatment for keratoconus and other corneal ectasias, but not all patients with these conditions qualify for this procedure.  Dr. Alanna Nattis is one of the few cornea specialists in the greater New York area who specializes in this procedure.  Contact SightMD to find out if you are a good candidate for Corneal collagen cross-linking.



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