FEB 2018

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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Page 126 of 150

EW RETINA 124 Research highlight by Maxine Lipner EyeWorld Senior Contributing Writer February 2018 Studying treatment effect of this laser technique F loaters are common, accord- ing to Chirag Shah, MD, MPH, assistant professor, Tufts University School of Medicine, Boston. Patients who are in their 50s through their 70s who have developed a posterior vitreous detachment are commonly bothered by pesky floater strands, he finds. In a study published in JAMA Ophthalmology, investigators consid- ered the effect of YAG vitreolysis on such floaters. 1 The study grew out of Dr. Shah's experience while pre- paring a lecture on floaters. "In the process of putting this presentation together, I recognized that there was a tremendous unmet need in terms of research for symptomatic float- ers," he said. "There are a handful of providers in the country performing YAG vitreolysis, but there was lim- ited data, and there were no ran- domized prospective clinical trials." There is a need for patients with floaters who do not wish to undergo vitrectomy to have an option such as YAG vitreolysis, so Dr. Shah decid- ed to launch a study on this. Fielding floaters with YAG vitreolysis Fun fact The layer deposition manufacturing used to create this implant was awarded the opportunity to be tested on the International Space Station, allowing researchers to look at the effects of microgravity on this process. "We hypothesize that in the absence of gravity, we will get more homogenous layering, which may influence the lifetime and stability of the thin films. The results of these studies could have a significant impact on the field of layer-by-layer manufacturing extending beyond the retinal implant," Dr. Wagner said. "What those experiments demonstrated is if we have no im- plant there, you'll see no signals, the ganglion cells are not responding, and when we put our implant in an orientation where we should be pumping ions toward the cells we get a signal." This, she continued, demonstrated a proof of concept for the experiment and implant itself. LambdaVision is currently testing in vivo in animals, looking at the toler- ability of the implant; human trials are expected to begin in 2–3 years, pending success of the preclinical trials. From a surgical standpoint, electrode-based implants can take 4–8 hours to place, according to Dr. Wagner. The procedure for the LambdaVision implant, in contrast, will be similar to a retinal detach- ment procedure with currently available surgical tools. The implant will be placed subretintally as close to the fovea as possible, due to its high density of neuronal cells. Stud- ies are currently underway to evalu- ate the optimal size and shape of the implant to be placed reliably and reproducibly in the retina, while still achieving maximum efficacy, Dr. Wagner said. "The protein-based retinal im- plant under development by Lamb- daVision will have broad societal impacts that will benefit millions of people across the globe," Dr. Wagner said. "Of paramount importance is the fact that our retinal prosthet- ic will offer patients a treatment option that can restore functional vision following the devastating pathological advancement of retinal degeneration. Retinal degenerative diseases like RP and AMD have so far been considered incurable diseases, and while treatments are marginally successful in slowing progression, permanent blindness is the inevitable end result. Restoring vision for these people will have tremendous impacts on quality of life for patients and families who are directly affected by these diseases. We also think the work we are doing is paving the way for future retinal implant technologies." EW Editors' note: Dr. Wagner has financial interests with LambdaVision. Contact information Wagner: nicole.wagner@lambdavision.com Light-activated continued from page 122 Studying YAG treatment Included here were 52 patients who had symptomatic Weiss ring floaters for at least 6 months. Patients in the study were randomized in a 2 to 1 fashion to either undergo real YAG vitreolysis or treatment with a sham laser, Dr. Shah explained, adding that just a single laser treatment was done for the purposes of the trial. Patients were seen at 1 week, 1 month, and 6 months after the treatment or sham procedure. "One of the main things we were evaluating was safety, in addition to efficacy," Dr. Shah said. "After 6 months, we repeated the questionnaires—including the VFQ- 25—to determine if we made any impact on quality of life or quality of vision." Photographs of the eye were taken at the beginning and repeated at the 6-month mark so that a masked investigator could look for objective changes in floater appearance. Results indicated that the treatment was moderately success- ful. "Patients on average reported a 54% improvement after the single session of YAG vitreolysis," Dr. Shah said, adding that 53% of patients reported either a significant or a complete resolution of floaters at the 6-month mark. When a masked grader looked at the floaters, this rate was much higher. "Objective- ly, 94% of the eyes treated had significant or complete resolution of floaters when looking at color photography by a masked grader," Dr. Shah said. "There is a disconnect in what we see clinically, so even if you think you have vaporized all of the floaters, patients might not be happy." The discrepancy between objective and subjective outcomes needs to be further researched to determine which floater types and which patient types are helped the most, he said. Dr. Shah pointed out that just a single YAG vitreolysis session was done, whereas in real life, patients would undergo two or three treat- ments. The reason for this was the fear that those who were undergo- ing the sham laser treatments were likely to realize they were not get- ting the real laser and inadvertently unmask themselves. Investigators did find a small placebo effect with the one session, with the sham group reporting a 9% improvement. "But the median was 0%," Dr. Shah said, adding that the majority of patients in the sham group reported no symptomatic improvement. There were no clinically signif- icant adverse effects in the la- ser-treated group, Dr. Shah reported. In one case, he inadvertently periph- erally pitted the patient's intraocular lens while working on some anterior floaters. There was also a patient in the sham group who suffered a complication. That patient, who had lattice degeneration at the time of enrollment, developed a retinal tear during the 6-month follow-up period. "What that indicates to me is that these patients with symptom- atic floaters may have an abnormal vitreous, and that vitreous can cause retinal tears even in the absence of any treatment," he said. "Things that we worry about like glaucoma, retinal detachment, retinal damage, or cataract formation did not occur in this small trial after 6 months of follow-up." Still, the study included 36 patients who were treated with YAG vitreolysis and 16 in the sham group, so it was not powered to find un- common adverse events. "We need larger studies preferably with longer follow-up to determine the true risks that can occur and the frequency of those risks," Dr. Shah said. continued on page 125

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