Eyeworld

EW INTERNATIONAL 76 July 2016 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer lessons from previous devices going unlearned, or possibly other reasons. The principle is not at fault, unless proven," he said. Iris-fixated lenses have the longest track record by far among PIOLs, of roughly 20 years. The surgical implantation can be de- manding, requiring a large incision and the full immersion of the IOL in the anterior chamber, which some surgeons may wish to avoid. Although the foldable model of the iris-claw lens is implanted using a smaller incision, it causes inflam- matory reactions with synechiae in 15% of cases in reports and in Dr. Neuhann's own experience. In his personal evaluation, he thinks the smaller incision size does not out- weigh the inflammatory risk. "I currently use the PMMA mod- el of the iris-fixated lens for myopias over 16 D, nominal, in cases where I would not use ICLs. I use it for rare cases of hypermetropia, in which the anterior segment has ample room, and for cases of astigmatism of more than 6 D, nominal, because that is the limit of the ICL, the iris-fixed lens available up to 8 D, nominal. So far, I have not had any cases of endothelial decompensation or explantation due to ongoing en- dothelial loss with this lens model," he said. Posterior chamber PIOLs have undergone an improvement with the addition of a central hole that promotes aqueous circulation and eliminates the need for an iridecto- my or iridotomy. The results in the literature are very good, according to Dr. Neuhann, with the lens' main complication in 2–3% being cataract formation, higher in high minus and plus lenses. "ICLs are my posterior PIOLs of choice in myopias below –16 D, when corneal surgery is not indicat- ed. I choose a toric IOL according to the highest myopic meridian. I do not use these in hyperopic eyes due to the low benefit in low hyperopia and the higher cataract incidence in higher hypermetropia," he said. EW Editors' note: Drs. Epstein and Neuhann have no financial interests related to their comments. Contact information Epstein: Epstein.dan9@gmail.com Neuhann: prof@neuhann.de procedure. He said that the spherical equivalent in patients over 40 years of age was more stable than in pa- tients below 40 years. Also, patients below –4.0 D were more stable than those above –4.0 D, which were notable outcomes, according to Dr. Epstein. Outcomes of PIOLs PIOLs are the method of choice when corneal laser surgery is not indicated or chosen by the patient. The visual outcomes are excellent and equal or superior to laser treat- ment, with a limited zone diameter. As far as "untold secrets" were concerned, Thomas Neuhann, MD, medical director and founder, Laser Eye Center, Munich, Germany, ad- mitted, "There are no secrets about what we know regarding PIOLs. Thanks to meetings, the Internet, and tabloids, the facts are out there." Dr. Neuhann explained the reasons he uses different PIOLs. "I prefer ICLs for eyes below –16 D, nominal, and torus limited to 6 D, nominal. I prefer iris fixation in ex- treme myopias, higher tori, limited to 8 D, nominal, and in hyperopic eyes, if there is enough space," he said at the symposium. Although he does not use angle-fixated PIOLs, Dr. Neuhann explained that bad results with any particular IOL should not necessar- ily discredit the principle behind the device, such as the case with angle-fixated PIOLs, which were abandoned due to endothelial cell loss. "This may show design flaws, surgical error, a company's inabil- ity to react to surgical experience, none in patients with hyperopia, ac- cording to several Cochrane reviews. Furthermore, outcomes were often unreliable and biased because of the failure to mask result assess- ments in most studies. The lack of controlled studies precluded any re- liable conclusions on these methods and were misleading, according to Dr. Epstein. Surface ablation Another surprising fact is the lack of significant evidence in favor of custom ablation over conventional ablation. A prospective, random- ized contralateral study showed in 80 myopic eyes using 1 laser that uncorrected distance visual acuity, corrected distance visual acuity, contrast sensitivity, and higher order aberrations were not significantly different between custom and con- ventional ablations, Dr. Epstein said. Surface ablation outcomes in a study that followed patients over the long term from 13 to 19 years were surprisingly good. The results in patients treated with PRK for refrac- tions as high as –20 D had postop- erative results within 1 D of aim at 6 months after surgery, despite low predictability and high incidence of haze. Another 16-year study showed similar outcomes with only slight regression, in spite of surgeries per- formed with early excimer units. Dr. Epstein said PRK was as- sociated with minimal regression, according to a number of studies. An 18-year follow-up report from patients who underwent PRK with low to moderate myopia revealed a regression of –0.43 D at 1 year and only –0.74 D at 18 years after the Specialists discussed tried and true refractive surgical practices at the 20th ESCRS Winter Meeting T wenty plus years and a strong body of evidence have rendered some once-popular refractive sur- gical practices obsolete and established others as here to stay. Experts at the 20th ESCRS Winter Meeting discussed the relevance of new and old methods in today's re- fractive surgical landscape, revealing some secrets and some surprises. Secret success of PRK "The biggest PRK secret is that the procedure never died. Oblivion was predicted when LASIK came along, but that never happened, and in some countries, PRK is even on the rise," said Daniel Epstein, MD, Zu- rich, Switzerland, in a talk he gave at the main symposium "Are there any untold secrets in refractive surgery?" PRK has stood the test of time and proved to be stable. Some evidence shows that patients who underwent PRK are more stable at 1 year after surgery than patients who underwent LASIK. Post-LASIK pa- tients undergo increases in corneal power over time, shown in 1 study to increase continually up to 7 years postoperatively, Dr. Epstein said. PRK seemingly got a bad rap early on as a result of poorly con- ducted studies, Dr. Epstein said. As it turns out, however, PRK, LASEK, and epi-LASIK are all the same, Dr. Epstein explained. Data from a me- ta-analysis from 2010 revealed that the outcomes for uncorrected visual acuity, spherical equivalent, reepi- thelialization, and pain between PRK and LASEK from 12 prospective, ran- domized trials showed no significant differences. "Sometimes you need to wait 15 to 20 years before the evidence is clear. This is an example of the kind of material evidence that is needed," Dr. Epstein explained. The problem is in the fact that although early reports showed significant differences between these methods, randomized, controlled trials for PRK and LASIK were few and far between. There were only a handful of reliable PRK and LASIK studies in patients with myopia and Time-tested refractive corrections Presentation spotlight " The biggest PRK secret is that the procedure never died. Oblivion was predicted when LASIK came along, but that never happened, and in some countries, PRK is even on the rise. " –Daniel Epstein, MD

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