Corneal Cross-Linking

Corneal cross-linking to treat Keratoconus and Corneal Ectasia

Some diseases change the middle layer of the cornea, causing it to get thinner and weaker. This thin cornea bulges into an irregular shape, which can cause your vision may become blurry, your eyes may be bothered by bright lights and your vision may get worse over time. The medical name for this type of corneal diseases is called corneal ectasia, and there are several types. The most common type is called keratoconus. Keratoconus usually starts during the teen years and progresses through young adulthood. Another type is called post-refractive ectasia and starts after eye surgery such as LASIK. 

The cornea is the clear, outer layer of your eye and has 5 layers. The middle layer, called the stromal layer, is the thickest part of the cornea. It has mostly water and a protein called collagen. Collagen makes the cornea strong and flexible. It also helps the cornea keep its round, regular shape. A healthy cornea focuses light so you can see clearly. 

Our doctors use a procedure called corneal cross-linking, or CXL, to stop the cornea from getting thinner, weaker and more irregular in shape. Although CXL cannot make your cornea normal again, it may keep your vision from getting worse. Sometimes, your vision may even improve. But you may still need to wear glasses or contact lenses for near or far vision. It is possible that your eye may start getting weak again. If it does, you may need another CXL treatment or another type of cornea surgery. 

Corneal cross-linking (CXL) can help make the middle layer stronger 

CXL can be done as a scheduled minor procedure with topical anesthesia (numbing drops/gel) and takes about 1.5 hours to perform. We usually do 1 eye at a time. 

There are 3 steps in the treatment: 

  1. Numb your eye with drops and then gently remove part of the outer layer of your cornea. 
  2. Put special vitamin eye drops (riboflavin) on your eye many times for about 30 minutes. 
  3. Shine a special ultra-violet (UV) light on your eye for another 30 minutes and keep adding drops. The vitamin eye drops and UV light work together to make the collagen stronger. The cornea becomes stiffer and usually stops bulging out. 
Eyedrops and UV light strengthen your cornea

Other treatment options

There are other ways to treat your weak cornea. Your ophthalmologist will talk to you about which treatment would work best for you. 

  1. You may be able to wear glasses and special contact lenses to see better. But they do not treat or stop your eye problem. So if the cornea keeps getting thinner and weaker, glasses or contact lenses may not be enough. 
  2. Your ophthalmologist could put small, clear plastic inserts inside your cornea (corneal ring segments) to help flatten the cornea. 
  3. Some people may need corneal transplant surgery. 


There are risks (problems) that can happen with CXL. Here are some of the most common or serious: 

  • Pain. You will probably feel pain and be sensitive to light for a few days. You will get a prescription for medication to help with the pain. 
  • Infection. You could get an eye infection from the surgery. The infection might cause your cornea to scar and make your vision worse. You will get a prescription for eye drops to help prevent an infection. If you had an eye infection called HSV (herpes simplex virus) in the past, it could come back. 
  • Vision problems. Your vision will be poor for a few days or weeks. This poor vision may last longer if you have an infection or your eye does not heal well. Your vision may stay this way. 
  • Healing problems. Your cornea might not heal well, or it might take a long time to heal. It could become cloudy instead of clear (corneal scarring). 
  • Your cornea may keep changing shape for many months. You may need to get new glasses or contact lenses while the shape is changing, and again after the shape stops changing. 

One CXL treatment may not be enough. Your cornea could get weak and thin again, or more irregular. If it does, you may need another CXL treatment or another type of cornea surgery.