Risk of Corneal Cross Linking?

Dr. Kisling Kerataconus Leave a Comment

Is There A Risk of Corneal Cross Linking?

Corneal cross linking is a new procedure used to help stabilize the cornea in the case of keratoconus or ectasia (a bulging of the cornea after LASIK surgery. The procedure involves applying riboflavin drops (Vitamin B12) to the surface of the eye then treating the surface with UVA radiation. There has been some concern that the exposure to ultraviolet radiation may lead to melanomas inside the eye.

Risk of a Melanoma From Corneal Cross Linking

UVA activates melanin (the colored pigment) that is already present and the effect is temporary. UVB would be more of a concern if it was being used as it does cause the creation of new melanocytes, the cells that produce melanin.


The other factor to consider is the dosage received during the procedure. The total dose is supposed to be about the same as a full day in the sun. That is just on the surface of the eye. The riboflavin drops help decrease the amount of exposure by 95% by the time it reaches the back of the cornea. Then it is reduced by half again as it passed through the lens. At least in theory, you are probably getting a dose of less than .08 milliwatts per square cm. At 8 ten thousandths of a watt you probably don’t have much to be concerned with. As best as I can figure you get a dose equal to less than 10 minutes spent outdoors.

The third factor to consider is the actual wavelength of ultraviolet light used. The wavelength used (370 nanometers) is in the low end of damaging radiation for UV. It is felt that once the UV gets partially through the cornea there is inadequate energy to cause cellular damage.

About 5-7% of the population will have a freckle in the back of their eye. The rate of transformation of a freckle to a melanoma is rare. One researcher estimated about 1 in 8800. I think it is probably less than that.  It is unlikely that there is a risk form corneal cross linking in developing a melanoma inside the eye. The risk of transformation from the higher altitude UV exposure in the Fort Collins area probably greatly outweighs the risk (if any) of corneal cross linking, even though it is rare.

You can find more information about keratoconus at: Keratoconus Information

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