Cross-linking the cornea (CXL)

Corneal cross-linking (CXL) is a technique that combines UV light (UV-A) and riboflavin (vitamin B2) to cause a photochemical reaction that mechanically stiffens the cornea by increasing the number of crosslinks in collagen.

After several years of basic research, CXL was introduced to ophthalmology in 1999. In 2004, Prof. Hafezi was part of the Zurich team that developed the first irradiation lamp. CXL has become the global gold standard for the treatment of keratoconus and other corneal ectasias, and  an estimated 200,000 treatments are performed each year.

Cross-Linking (CXL)

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Cross-Linking on Video


The effect of the CXL is almost immediate and leads to a mechanical stiffening of the cornea – by about 450%, and the effect is detectable just hours after CXL. The success rate of the CXL according to the medical literature is well over 90%.


CXL’s safety has been demonstrated time and time again in countless studies: currently (as of November 2020), more than 2,000 peer-reviewed scientific articles can be found in the medical databases. Our group has contributed over 100 articles, representing 5% of the world’s scientific literature on CXL alone.

CXL performed with C-Eye Device

Which technique is for me?

Nowadays, a variety of variations of the cross-linking technology exist and the range of applications has been increased. The treating ophthalmologist not only needs to be familiar with all these new techniques, but also to assess which technique is scientifically sound enough to be used on a case-by-case basis.

The ELZA Institute