Keratoconus is a rare condition affecting people between the ages of 10 and 25 and may progress slowly.
Keratoconus occurs when the cornea (the clear outer layer at the front of the eye) becomes thin and gradually bulges outward into a cone shape. This condition causes optical irregularities that affect vision. Symptoms include blurred and distorted vision, astigmatism, double vision, inability to see in dim light, nearsightedness, sensitivity to light, and/or vision loss.
Normal Cornea vs. Keratoconic
Cornea Vision Simulator
The Importance of FDA-Approved Cross-Linking
In April 2016, the FDA approved Avedro’s corneal cross-linking procedure with the Photrexa drug formulations and the KXL® System to slow or halt the progression of the disease, giving patients an effective, minimally invasive treatment option. Corneal cross-linking is a medical procedure combining the use of ultra-violet (UV) light and riboflavin (vitamin B2) eye drops. The procedure works by creating new corneal collagen cross-links, which results in a shortening and thickening of collagen fibrils that lead to the strengthening of the cornea. Cross-linking, which has been performed in Europe since 2003, is considered the standard of care around the world for keratoconus.
- FDA approved therapeutic treatment available for progressive
keratoconus and corneal ectasia following refractive surgery.
- Can limit the progression of the disease by stiffening the cornea.
- Clinical benefits of reduction in maximum corneal curvature.
- Ulcerative keratitis, and/or a potentially serious eye infection, can occur.
- The most common ocular adverse events were corneal opacity, punctate keratitis, corneal striae, corneal epithelial defect, dry eye, eye pain, reduced visual acuity, photophobia, and blurred vision.
- The majority of these adverse events resolved in the first month.
Frequent Asked Questions
Corneal Cross-Linking with the AVEDRO KXL System is FDA approved for the treatment of Progressive Keratoconus. This means for keratoconic patients who’s vision continues to change and or their corneal shape continues to change over time.
Keratoconus, often referred to as ‘KCN’, is an eye condition in which the cornea weakens and thins over time, causing the development of a cone-like bulge and optical irregularity of the cornea. Keratoconus can result in significant visual loss and may lead to corneal transplant in severe cases.
Cross-linking is a minimally invasive outpatient procedure for the treatment of progressive keratoconus. FDA approved epi-off cross-linking combines the use of eye drops containing riboflavin (Photrexa® and Photrexa® Viscous), and ultra-violet A (UVA) light from the KXL® system to create new collagen cross-links which leads to the stiffening of the cornea. The goal of the procedure is to stiffen the cornea to slow or prevent further progression of the condition and preserve vision.
The cross-linking procedure takes about an hour. Patients relax reclined on a surgery bed for the procedure. Numbing drops are used to anesthetize the eye so there is no discomfort.
The CXL procedure has 3 steps:
First, a very thin layer of cells on the surface of the cornea, the epithelium, is gently brushed off to allow better absorption of the riboflavin drops into the cornea.
Second, a series of riboflavin drops are applied to the cornea over several minutes. The doctor may evaluate your eye to ensure the cornea has absorbed a sufficient amount of riboflavin.
The last step is to check the corneal thickness and then apply the UV light for up to 30 minutes. The UV light comes from a specialized lamp that will be placed above the eye.
After the procedure is completed a contact lens will be placed on the eye to act as a protective “bandage”. This contact lens will remain on the eye for several days until the doctor feels your eye has healed sufficiently. The doctor will also prescribe medicated eye drops to use for several weeks.
Ultra-Violet A Light is one of the types of light that is present in the sun. These rays of light are used in the chemical reaction for the Corneal Cross-Linking procedure. The UVA light emitted from the KXL System is very controlled and is only applied to the area of the cornea.
Corneal Cross-Linking (CXL) can be performed with or without removing the epithelium. In the United States, the only FDA approved method for CXL is to remove the epithelium. In studies, it has been shown that removing the corneal epithelium allows better penetration of the riboflavin into the cornea which makes the cross-linking procedure more effective.
Yes, patients are awake during the cross-linking procedure. Because numbing or anesthetic drops are applied to the eye before the procedure you will not feel any discomfort. It’s also important to be awake so that you can concentrate on looking straight ahead during the procedure.
The treatment takes about an hour. The total time patients are in the office is about an hour and a half.
Because the surface epithelium of the cornea is removed there can be some discomfort, burning, and stinging for a couple of days after the CXL procedure. To help with the discomfort patients are prescribed eye drops and pain medication that can be used if needed. Also, a bandage contact lens will be placed on the eye as well to aid in healing and to help with comfort. The vision can be quite blurry for a couple of days during this time. Once the contact lens is removed in about a week the vision will improve. Most patients are able to drive and return to work in this first week.
Because numbing or anesthetic drops are applied to the eye before the procedure you will not feel any discomfort. After the procedure, patients may experience burning, stinging, and light sensitivity after the anesthetic drops wear off. These symptoms will come and go over the next several days as your eye heals.
The CXL procedure will not change your appearance. The cross-linking reaction that occurs, deep in the layers of the cornea, is microscopic. You will not be able to see this with the naked eye.
After a thorough evaluation with the doctor, he/she will be able to determine if Corneal Cross-Linking is a good option. It’s best for the doctor to review previous eye exam records to determine how much your vision has changed over time. Depending on how progressive your condition helps to determine if Corneal Cross-Linking is the best option for each patient.
We recommend that patients not wear their contact lenses for at least 24 hours before the procedure. After the procedure, a soft contact lens will be placed in the eye for about a week to aid healing. The doctor will advise the patient, depending on their type of contact lens and their situation when it would be appropriate to start wearing their regular contact lenses.
Most insurance plans now cover the cost of corneal cross-linking. This can be verified by a staff member before the Cross-Linking procedure.