Keratoconus is now treatable through a procedure called corneal collagen cross-linking (CXL).
How It Works
Your surgeon applies a photosensitizing solution containing riboflavin (vitamin B2) to the cornea, then exposes it to a low dose of ultraviolet light. The reaction between the photosensitizer and the ultraviolet light creates new collagen bonds, or cross-links, throughout the cornea.
First, the epithelium is gently rubbed off to allow for absorption of the riboflavin. Then, the riboflavin drop and ultraviolet light are applied for approximately 30 minutes. Once the procedure is complete, the eye is covered with a bandage contact lens to help the epithelium grow back (normally within 2 to 5 days) and facilitate a quick visual recovery.
CXL strengthens and adds resilience to affected corneas by creating new collagen bonds. If performed early enough, CXL can counteract the effects of keratoconus and preserve good vision. In more advances cases, CXL—often combined with other types of treatment—can postpone the need for invasive corneal transplants and prevent vision from deteriorating.
CXL is unique in that it is non-invasive and targets the source of the problem, which is the weakened cornea due to keratoconus. The treatment significantly increases the number of collagen bonds between the corneal layers, returning the cornea to a more stable condition.
The ultraviolet light used for CXL was specifically chosen because it is safe for the cornea, lens, and retina, but still sufficient to induce collagen cross-linking. Ultraviolet light is measured and calibrated before each treatment to ensure safe exposure levels, and clinical studies have demonstrated that the amount of light that reaches the deeper structures in the eye is not enough to cause damage.
What to Expect
CXL is performed in a treatment room under topical anaesthesia—the procedure is uncomplicated and painless. While vision typically returns to prior levels within one week, the most dramatic improvements occur over the first three months. Then gradually, over the next 12 months, the cornea continues to stiffen and stabilize resulting in further improvements. In most cases, the keratoconus ceases to progress and, in some cases, vision improves. Patients will usually be seen daily to assess initial healing. The bandage contact lens is then removed about 3 to 5 days after treatment. In most cases, patients may return to wearing contact lenses for their prescriptions after one month. Contacts, however, may need to be changed occasionally until the cornea fully stabilizes.