Eyeworld

EW RETINA 62 October 2015 by Michelle Dalton EyeWorld Contributing Writer Newer diagnostics for AMD What anterior segment surgeons need to know about diagnosing AMD I n the years since the antivas- cular endothelial growth factor drugs were introduced, treating age-related macular degener- ation (AMD) has become less about delaying disease progression and more about reversing the dam- age already done. Part of that strategy includes being able to diagnose the disease earlier and earlier. A genetics task force is planning a report this fall to address the potential benefit of genetic testing and/or vitamin use in the realm of retinal disorders, but details were not available at press time. Diagnostic tools Optical coherence tomography (OCT) is typically used to confirm treatment efficacy. Whether or not OCT-angiography, one of the newer tools, is clinically useful is still being debated. On the one hand, "OCT-A does not show leakage, which is what matters," said Steve Charles, MD, Charles Retina Institute, Germantown, Tenn., who added spectral domain OCT "is the optimal way to determine who needs an injection and who does not." But "it's quite exciting to be able to find choroidal neovascular- ization (CNV) using OCT-A, where that information is already captured in many of the machines that we have," said J. Michael Jumper, MD, West Coast Retina, San Francisco. "OCT-A is mostly software changes that could, hopefully, allow us to be able to see CNV without having to do a fluorescein angiogram." While he agrees there are some limitations to the technology, "it'll put angiog- raphy in the hands of more people," he said. Whether the technology will allow clinicians to readily identify choroidal neovasculariza- tion better than current technology remains to be seen. Dr. Charles firmly believes OCT-A "is not a game changer." The technology will continue to be aca- demically interesting, "and may be a research tool," but "it has a tremen- dous problem with motion artifacts" that will prevent it from becoming a highly valuable clinical tool. Dr. Jumper said diagnostic tools such as the AMD home monitoring devices "seem to have real value." The ForeseeHome AMD Monitoring Program (Notal Vision, Chantilly, Va.) monitors progression of AMD and appears to be more sensitive in detecting early changes. It's the first commercially available home moni- toring device. "It's possible these devices can help improve outcomes in people with AMD by detecting choroidal neovascularization earlier," Dr. Jumper said. The test results are transmitted to a central monitoring system that will alert physicians to immediate, significant visual field changes in their patients, so that patients can be recalled for timely follow-up and necessary treatment may be initiated. Encapsulated cell technology Dr. Charles said "the real research" being done at the molecular level and with molecular targeting "is what the next phase is all about." Encapsulated Cell Therapy (ECT, Neurotech, Cumberland, R.I.) is a first-in-class, versatile drug delivery platform in development for the treatment of a broad array of ocular disorders. ECT is "a genetically engineered ocular implant that enables continuous production of therapeutic proteins to the eye for more than 2 years. Additionally, the therapy is reversible by simply removing the implant," the compa- ny said. The potential is great, Dr. Charles said, especially for rural patients who cannot afford monthly visits to a retina clinic or who have physical limitations where getting to a retina clinic is difficult. ECT "has a track record in reti- nitis pigmentosa," Dr. Jumper said, and "may have a role" in AMD. Sim- ply put, ECT uses living cells "en- capsulated" within semipermeable polymer membranes and supportive matrices. The technology allows a therapeutic agent to be engineered into the cells; by encapsulating the cells the technology prevents immune system rejection while still allowing the therapeutic product to disseminate to their target sites. "Unlike gene therapy, this tech- nology is reversible, which makes it more attractive," Dr. Charles said. Drug reservoirs Numerous retinal disorders man- date monthly monitoring and/ or treatment, and "refillable drug delivery devices may one day be the thing that's going to help decrease the retreatment rate," Dr. Jumper said. But the technology would bring with it as many questions as it addresses, namely cost, implantation techniques, and patient selection, among others. Device focus Source: "Bayer Germany Retina Image Collection," produced by Karl Brasse, MD Above, patient being examined with optical coherence tomography (OCT); below, fluorescein angiogram to help determine disease state

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