New Orleans—Though the main benefit of collagen corneal crosslinking is to stop progression of keratoconus, it is not the sole benefit, said Theo Seiler, MD, PhD (Greece) here during Cornea Day at ASCRS 2016.
Before surgeons can qualify what is a success, they must also define the failure.
“Long-term studies of the Dresden protocol revealed a failure rate as low as 3%,” he said.
In that protocol, complication rates hovered around 4%, and corneal flattening of more than 2 D occurred in more than 13% of the cases. But other studies reported varying rates, adding to the debate about how efficacious and safe the procedure is—and which techniques may bring the best results.
Some studies defined failure as an increase of more than 1D of Kmax as a failure, but other studies report a failure rate at year 2 of only 2%. One study reported the 4-year failure rate at 0%, “but there were only 40 eyes enrolled,” Dr. Seiler said.
Safety of the procedure is equally important, he said. Using the FDA definition of a loss of 2 or more Snellen lines to indicate a complication, rates vary from 13.7% in India and Iran to a low of 0% in England. The social environment in the two regions may contribute to the complication rates, he said, as England has stricter follow-up regimens.
In the past 10 years, there have been several changes proposed to the Dresden protocol, but only a select few have been useful. For instance, transepithelial crosslinking resulted in a shallower effect leading to a re-treatment rate of up to 50%, “which is obviously not acceptable,” Dr. Seiler said.
Thinking that there may not be consequences to the procedure or that it is just a cornea procedure would be ill advised, he said.
He then described a case of documented progression in a patient who underwent crosslinking. At the 1-year follow-up, the patient was happy, there was “a nice regression” of the keratoconus, and “I was the patient’s hero. He could drive without glasses,” Dr. Seiler said.
But unfortunately, crosslinking is not always a “one-and-done” procedure—in this case, after 9 years the patient is now hyperopic but without astigmatism.
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