EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/1261109
32 | EYEWORLD | JUNE/JULY 2020 by Liz Hillman Editorial Co-Director R PHARMACEUTICAL FOCUS EFRACTIVE C rosslinking is interesting in that it has both pharmaceutical and device components that cause a reaction to stiffen collagen fibrils and create linkages between the cornea's struc- tural components, but the procedure has moved in some ways beyond the initial riboflavin soak followed by UV light exposure. Since it was first described by Theo Seiler, MD, PhD, in the 1990s, crosslinking has seen some evolution while preserving its goal of stopping progression of corneal steepening in patients with keratoconus or post-LASIK ecta- sia. The Dresden protocol—an epithelium-off procedure with a riboflavin soak and subse- quent UV light exposure on corneas of at least 400 µm—with drug and device components by Avedro (now owned by Glaukos) remains the FDA-approved procedure in the U.S. But change could be coming. For example, the company is conducting a Phase 3 randomized clinical trial to evaluate the safety and efficacy of epithelium-on crosslinking. EyeWorld spoke with William Dupps, MD, PhD, Joseph Ciolino, MD, and Michael Raizman, MD, about their thoughts on the current status of crosslinking in the U.S. and its future. In short, they thought a customizable pro- cedure is on the horizon. "Crosslinking [in the U.S.] is currently the closest thing to a one-size-fits-all procedure that we do in anterior segment surgery," Dr. Dupps said. Customization with various techniques might improve outcomes for patients eligible for treatment under the current protocol and/ or extend treatment to patients currently ex- cluded. Epi-on vs. epi-off There is overwhelming evidence in the litera- ture that an epi-off procedure results in greater stiffening and halting or even partial reversal of progression compared to most epi-on pro- tocols. But Dr. Dupps pointed out that there is much variability in approaches to improve riboflavin penetration through the epithelium— addition of supplemental oxygen, chemical irri- tants, mechanical irritation, iontophoresis, etc. "Epi-on is not one procedure," he said, adding that this "makes it difficult for people to read the literature and draw conclusions between epi-on vs. epi-off." Dr. Raizman said with all other variables the same, epi-on crosslinking is less effective. "That's without question." Dr. Ciolino said unless there is a contra- indication, he'll perform epi-off crosslinking, though he discusses the option of epi-on with his patients, most of whom, he said, elect to have epi-off. He said colleagues from Europe recommended use of an Orca blade (Orca Sur- gical) to remove the epithelium and a regimen of postoperative autologous serum tears with a Taking a look at the future of crosslinking About the doctors Joseph Ciolino, MD Associate professor of ophthalmology Harvard Medical School Massachusetts Eye & Ear Infirmary Boston, Massachusetts William Dupps, MD, PhD Professor of ophthalmology Cleveland Clinic Lerner College of Medicine Cleveland, Ohio Michael Raizman, MD Associate professor of ophthalmology Tufts University School of Medicine Boston, Massachusetts UV light and red aiming/focusing beams on the cornea during crosslinking procedure Source: Michael Raizman, MD