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Panelists differ in approach to suggesting cross-linking for keratoconus
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NEW ORLEANS – Corneal collagen cross-linking has not yet received FDA approval; however, many optometrists are recommending the procedure for their patients with keratoconus, according to a panel here at the Optometric Council on Refractive Technology.
The audience at the symposium, which was held in conjunction with the American Academy of Optometry meeting, agreed that clinicians need not fear malpractice claims for not recommending corneal collagen cross-linking (CXL), but the procedure is considered standard of care for keratoconus worldwide, panel members said.
Panelist Bill Tullo, OD, FAAO, DiplAAO, said he would refer a patient with keratoconus to a corneal specialist who performs CXL, while not specifically referring that patient for CXL.
Barry Eiden, OD, FAAO, said he is “very aggressive” in his practice.
Barry Eiden
“We tell patients it’s not FDA approved, but worldwide it is standard of care, and the efficacy of this treatment in halting the progression of the disease for their child is significant,” he said. “I’d say the reason why it’s not approved has nothing to do with the clinical efficacy of the treatment; it has more to do with administrative issues.”
Andrew Morgenstern, OD, FAAO, said he tells his patients that CXL is a safe and effective procedure performed outside of the U.S. and that it is approved in every country where it can be performed.
“The FDA did not like the way the study was organized,” he added.
“The majority of the response of the expert panel was favorable in having CXL approved,” Clark Chang, OD, MSA, MSc, FAAO, said. “It comes down to a technicality with an issue with the study designs.
Clark Chang
Andrew Morgenstern
“Keratoconus is very difficult to study,” he continued. “If you want to show efficacy of treatment, do you treat one eye and then wait to treat the other eye? Is that ethical?”
Tullo noted: “There is no such thing as unilateral keratoconus. You are born with the same type of collagen in both eyes.”
Morgenstern agreed. “If you have abnormal collagen in one eye, the collagen in the other eye has to be assumed to be abnormal,” he said.
Chang shared some study results with the audience, noting that most patients followed from 1 to 3 years show a success rate between 92% and 98%.
The panelists also discussed at what age a patient can be referred for CXL.
“If a patient is getting worse and they’re old, they need to be watched,” Tullo said. “But in the real world, age is irrelevant. I don’t care if they’re 9 or 10 or 15; I’ll find a surgeon who is doing cross-linking outside of an FDA study. I think it’s the right thing to do.”
Morgenstern shared some key conclusions from the Global Consensus on Keratoconus and Ectatic Diseases, which was published in April in Cornea.
Findings that he said are considered mandatory for a keratoconus diagnosis are: abnormal posterior ectasia, abnormal corneal thickness distribution and clinical noninflammatory corneal thinning.
The consensus on testing was to perform tomography (with Scheimpflug or optical coherence tomography), and posterior corneal elevation abnormalities must be present to diagnose mild or subclinical keratoconus, Morgenstern said.
“A less reliable indicator for determinant was central pachymetry,” he said. “This is because keratoconus can be present in a cornea of normal thickness.”
Morgenstern added that the paper said younger patients should be examined for change at shorter intervals, as ectatic change can progress rapidly in this group. – by Nancy Hemphill, ELS, FAAO
Disclosures: Chang reports no relevant financial disclosures. Eiden, Morgenstern and Tullo are consultants for Oculus.