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EW SHOW DAILY 16 E pithelium-on corneal collagen crosslinking ap- pears to offer great promise to simplify and increase the safety of the procedure but skeptics warn that published proof remains to be seen. Most of the potentially serious complications that have arisen in collagen crosslinking cases were the result of epithelial removal, R. Doyle Stulting, MD, Atlanta, said at a crosslinking symposium jointly sponsored by the ASCRS Cornea and Refractive Surgery Clinical Committees. "We would all like to do epi-on; I would like to do epi-on," David T. Vroman, MD, Ladson, S.C., said about the potential to avoid compli- cations. "And with continuing modifications and more study it will hopefully be shown as just as effective as epi-off, but currently the literature still supports epi-off." Supporters of the move toward epi-on cite unpublished research from the CXL-USA Study Group, which found epi-on and epi-off provided similar clinical and visual outcomes, including mean improvements of about one line of UVA and BCVA. "In our large and growing series at CXL-USA, we have seen no differ- ence," said John Hovanesian, MD, Laguna Hills, Calif. "Epithelium-on crosslinking is just as effective as epithelium-off, with fewer risks." Published risks to epithelium-off crosslinking include corneal edema, sterile infiltrates, infectious keratitis, and delayed epithelial, Dr. Stulting said. "Most of these complications are the result of epithelial removal, which leads to the efforts to figure out how to accomplish effective corneal collagen crosslinking with epithelium on," Dr. Stulting said. Tuesday, April 29, 2014 ASCRS Symposia Collagen crosslinking epithelium removal at issue Despite its potentially serious complications from epithelium-off crosslinking, which occur at as-yet- unknown rates among patients, the procedure will continue to have a valuable role because of growing efforts to combine other treatments with it. "The basic science supports epi-off, and combination therapy, that we would all like to have access to, may necessitate epi-off," Dr. Vroman said. "So we can't end the discussion on epi-off." Among the combination proce- dures with epithelium off showing "remarkable results" is topography- guided PRK followed by corneal collagen crosslinking. "And this necessitates epithe- lium off," Dr. Vroman said. But epithelium-on crosslinking has other uses, such as its ability to prolong the refractive effects of conductive keratoplasty. Other unanswered questions about the collagen crosslinking treatment include its role as an anti-infective treatment. In recent years, corneal collagen crosslinking has become an established treatment for arresting the progression of ecstatic corneal disorders, including keratoconus and pellucid marginal degeneration. But transfusion medicine has successfully used the photochemical reaction of riboflavin and UVA to inactivate various micro-organisms in blood products, and that led researchers to explore the benefits of collagen crosslinking in microbial keratitis cases, said Thomas John, MD, Oak Brook, Ill. However, Dr. John was critical of the existing clinical studies examin- ing the treatment's potential in microbial keratitis cases. For in- stance, the studies lacked homo- geneity for predisposing factors, clinical presentation, responsible organisms, and treatment durations. Importantly, the results almost all were confounded by concurrent use of medical therapy. "These clinical reports seem to indicate that collagen crosslinking may be an option in the treatment of keratitis but one cannot conclu- sively say it is effective," Dr. John said. "One has to continue our accepted standard of care antibiotic treatment in these situations." Research on the treatment's use in pseudophakic bullous keratopa- thy found it temporarily reduced pain, without providing long-term BCVA improvement. EW Editors' note: Dr. Stulting has financial interests with Abbott Medical Optics and other ophthalmic companies. Dr. Vroman has financial interests with Alcon, Bausch + Lomb, and Glaukos. Dr. Hovanesian has financial interests with 800 Doctors and other ophthalmic companies. Dr. John has financial interests with Allergan and other ophthalmic companies. Dr. John speaks at the "Update on Corneal Collagen Crosslinking" symposium. by Rich Daly EyeWorld Contributing Writer "After flushing out the vis- coelastic, the surgery is now ended," he said. The vaulting of the lens was then correct. "The patient had a very good uncorrected visual acuity with a very small amount of astigmatism and she did not need correction for that," Dr. Beniz said. Meanwhile, I. Howard Fine, MD, while acknowledging that this patient only had a family history of keratoconus, took the opportunity to mention his experience with kera- toconus patients and lens surgery. "It's very difficult to do biome- try on [keratoconus] patients," Dr. Fine said. "It's difficult to choose an appropriate power lens. My experi- ence with doing cataract surgery in patients with keratoconus is that generally they are not very happy. Today, with the technology that we have, a good place to start may be with corneal crosslinking to address the keratoconus first." In the case of Dr. Beniz's pa- tient, Dr. Fine asked whether the lens also was sent back to the manu- facturer for analysis. "They are labeled with respect to length, but it could be wrong," Dr. Fine said. EW Editors' note: Drs. Beniz and Fine have no related financial interests. A case continued from page 14

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