Eyeworld

It's an important side note, however, because the transepithelial approach involves no epithelial re- moval, while epi-off does. PRK also involves epithelial removal, and it is a procedure of the past rather than of the future. "Most [research] efforts are with the epithelium on in order to expe- dite recovery of vision and patient comfort," Dr. Hersh said. "But we are looking at both, trying to refine the parameters." In the 50 eyes of 35 patients treated by Dr. Kanellopoulos, various refractive corrections have taken place. He has treated up to 3 D of myopia, hyperopia, and astigma- tism. PiXL is ideal for the low myopes that don't want surgery, even though they could get a good result from LASIK. "With treatments up to this range, it's safe, accurate, and impres- sively stable," Dr. Kanellopoulos said. "We're almost up to eight months now postoperatively." At this point, treating the higher degrees of hyperopia and myopia (+3 D and –3 D) are with the "epi-off" technique, he said. Regardless, PiXL has special implications for certain patient populations. "It addresses people who are afraid to undergo an excimer proce- dure," Dr. Kanellopoulos said. Those who previously thought a very small refractive error—like 0.75 D—was not worth correcting surgically might opt for PiXL. This is especially true for those with residual refractive error after previous refractive sur- gery. Presbyopic treatments are also possible. In a good way, crosslinking is not as new as some might think, which helps boost the procedure's safety profile. "We have now 15 years of experience with classic collagen crosslinking," Dr. Kanellopoulos said. "We're relatively familiar with all the pros and cons." Already, PiXL has obtained the CE mark in Europe, allowing sur- geons there to use it once Avedro launches it more widely. The procedure has the potential to eliminate many complications of refractive surgery as well, including scarred corneas and epithelial de- fects. Scientific papers are in press about PiXL—specifically in the Journal of Refractive Surgery and Clinical Ophthalmology—but were not yet published as of press time. Making sense of things William B. Trattler, MD, Center For Excellence in Eye Care, Miami, said that it makes sense that since crosslinking works for keratoconus to improve refractive error, it could do the same for healthy corneas. "The question is whether you can be specific in the amount of reshaping to have the desired refractive effect," Dr. Trattler said. Competition is fierce, with PRK, LASIK, and now ReLEx SMILE (Carl Zeiss Meditec, Jena, Germany), which all are great, precise tech- niques, he said. Also mentioned was CK (conductive keratoplasty), which uses radio waves to shrink corneal collagen and cause a refractive change. "The downside is that CK doesn't last a long time," Dr. Trattler said. "It's not a permanent proce- dure, unless CXL is performed shortly after the CL procedure. That's the goal of PiXL—to reduce small refractive errors in a precise and reproducible way. It's exciting technology if it works." EW Editors' note: Dr. Hersh is the medical monitor and has financial interests with Avedro. Dr. Kanellopoulos has financial interests with Avedro. Dr. Trattler has financial interests with LENSAR (Orlando, Fla.) and CXLO (San Diego). Contact information Hersh: phersh@vision-institute.com Kanellopoulos: ajkmd@mac.com Trattler: wtrattler@gmail.com April 2014

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