Eyeworld

102 September 2016 by Vanessa Caceres EyeWorld Contributing Writer and the prevalence of mCNV was 0.017%, or 41,100 adults. Women were more likely to be affected by mCNV. The prevalence of high myopia was higher than that reported before in Europe (2.7%) but still lower than that shown in Singapore (4.8%), Dr. Willis and coauthors reported. The diopter-adjusted prevalence of mCNV was lower than that shown in other population studies, which has ranged from 0.04% to 0.084%. This may be due to differences in the racial and ethnic makeup of study populations, the authors wrote. For instance, some studies have been done in populations with a higher number of Asians, who have a higher risk for pathologic myopia. The findings support previous research that show the main risk factors for progressive high myo- pia and mCNV are a high myopic refraction, female sex, and older age. "The increased risk of mCNV among women supports the theory that estrogen receptor expression, or oth- er external influences of estrogen, might enhance the development of mCNV," the authors wrote. Due to some exclusions from the NHANES and IRIS Registry, the estimates of progressive high myopia and mCNV from the study actually may be low, the authors noted. Although mCNV may affect only a small portion of the popula- tion, future research should address the risk factors, treatment patterns, and management strategies for it, Dr. Willis said. "While mCNV is rare, it has devastating consequences if left untreated," Dr. Willis said. "If clinicians have myopic patients complaining of vision loss or meta- morphopsia, I would recommend urgently referring those patients to a retina specialist, where an appro- priate diagnosis can be made with a dilated fundus exam in conjunction with ancillary ophthalmic imaging tests," he said. Tien Wong, MD, chair of oph- thalmology and director, Singapore National Eye Center, Duke-NUS Medical School, National University of Singapore, who has worked with studies on the prevalence of myo- pia in Singapore, said this research shows that high myopia and patho- logical myopia have been "under the around the U.S. The registry has information from 88 million office visits to 13,739 ophthalmologists and eyecare professionals, according to the AAO. This is the first time the IRIS Registry has been used to calcu- late eye disease prevalence. Tracking high myopia and mCNV Until now, there has been limited information about the burden of mCNV in the U.S., Dr. Willis said. "Previous estimates were done more than 20 years ago, had a small sam- ple size, and were not generalizable to the current U.S. population," he said. That's when investigators de- cided to turn to information from NHANES and the registry. Specifi- cally, they used data from the 2005 to 2008 NHANES and 2014 data from the IRIS Registry. The data from NHANES were used to track the prevalence of high myopia, and that prevalence was applied to the 2014 U.S. population census. Then, data from the registry were used to calculate the real-world prevalence rates of progressive high myopia and mCNV among highly myopic patients, the investigators wrote. Investigators discovered an estimated 3.92% prevalence of high myopia, or 9.6 million adults. The prevalence of progressive high my- opia was 0.33%, or 817,800 adults, The study was published in Oph- thalmology 1 and led by Jeffrey Willis, MD, a retina fellow at the University of California Davis Eye Center and a clinical research fellow at Genentech (South San Francisco). Investigators used information from adults who participated in the National Health and Nutrition Examination Study (NHANES) as well as the American Academy of Ophthalmology's (AAO) Intelligent Research in Sight (IRIS) Registry. The IRIS Registry collects data on practice patterns from elec- tronic health records used at par- ticipating ophthalmology practices Researchers use big data to track prevalence A large-scale study found that high myopia—6 D or more—affects 3.92% of the U.S. population. The study also esti- mates that 0.33% have progressive high myopia and 0.017% have my- opic choroidal neovascularization (mCNV). Yet what may be more remark- able than these findings is how investigators did their research. EW REFRACTIVE High myopia affects small part of U.S. population but may go underreported " Our research was exciting in that it showed that big data in ophthalmology could help us better understand the epidemiology of rare ophthalmic conditions in the U.S. " –Jeffrey Willis, MD

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