Eyeworld

EW REFRACTIVE SURGERY 34 May 2016 by Liz Hillman EyeWorld Staff Writer Upward trend of myopia attributed to environmental causes K ovin Naidoo, OD, PhD, CEO of the Brien Holden Vision Institute, Sydney, Australia, had a sense that the incidence rate of myopia was on the rise. When re- searchers at the institute conducted a systematic review of the available data on myopia rates and performed meta-analysis, Dr. Naidoo admitted that he "did not expect the numbers to come out as high as they did." The paper published in Ophthal- mology predicts that by 2050, nearly 50% of the world's population will be myopic, and almost 10% of these people will be considered highly myopic. 1 Myopia, Dr. Naidoo said, "is 1 of the biggest public health challenges of our time." The research included 145 stud- ies published since 1995, comprising 2.1 million people total. Conducting meta-analysis, the researchers then made projections for myopia rates each decade for the next 30 years. While myopic patients in 2010 comprised about 28.3% of the global population (1.950 billion people), the study authors predict 49.8% of the world population (4.758 billion people) will be nearsighted by 2050. One billion of them will be consid- ered highly myopic. The study authors cite "environ- mental factors (nurture), principally lifestyle changes resulting from a combination of decreased time outdoors and increased near work activities, among other factors" as the primary cause of this upward trend. More specifically, cultures more focused on computer screens and smartphones or those that put more pressure on education at a young age could be driving some of this. Considering these figures, Dr. Naidoo said the lack of discussion among eye health professionals surrounding myopia rates and inter- ventions needed to reverse them is frightening. Dr. Naidoo said practitioners have a responsibility to increase awareness about this trend and about interventions that could help prevent some level of myopia, in- cluding encouraging time outdoors for children. A widely circulated study published in the Journal of the American Medical Association in 2015 found that 40 extra minutes of outdoor activity at school reduced myopia incidence rates over 3 years in 6-year-old Chinese children. 2 "We are definitely arguing that prevention is great, but we are realistic in that we're not going to prevent all myopia from occur- ring just by sending kids outdoors, so there needs to be appropriate correction, there needs to be ap- propriate intervention," Dr. Naidoo said. As for the increased incidence rates for high myopes, Dr. Naidoo pointed out that prevention and myopia control are key for curbing additional ocular complications, such as blindness, cataracts, glauco- ma, and myopic macular degenera- tion. "I think myopia is going to create new impetus for research into treatment of retinal conditions, particularly myopic macular degen- eration," he said. Dr. Naidoo said further studies should include more research on the mechanism behind time spend outdoors and myopia prevention as well as gain more country-specific data on incidence rates. "At the end of the day, much of the planning that happens around eyecare doesn't happen at the global level, it happens at the country level," he said, explaining that while this study makes global projections, the issue of myopia might not hit home until more specific data for each country is obtained. While Zheng Wang, MD, director of the Aier Eye Hospital, Guangzhou, China, said there is no exact number on the prevalence of myopia in China, "everyone agrees that it's higher than the global average, and it has been rising in the past decades." "As a matter of fact, very few high school students are not myopic nowadays," Dr. Wang added, saying Study predicts 50% of the global population will be myopic by 2050 C onsider this prediction: 4.758 billion people—nearly 50% of the world population—could be myopic by the year 2050. That's a pretty staggering number. In this month's "Refractive editor's corner of the world," we look at a meta- analysis in Ophthalmology that included 145 studies published since 1995. The study authors track an upward trend in the next 4 decades in the rate of myopia at a global scale. While technological advancement has improved many aspects of daily life for people around the world, 1 of the most significant environmental factors driving a more myopic population is a lifestyle that is primarily indoors. Previous studies have established that increasing time outdoors can help reduce incidence of myopia. This month's column speaks with 1 of the study co-authors about the research and also brings in refractive experts to comment on the state of myopia in their own countries and what they think could be done from a prevention standpoint. Steven Schallhorn, MD, refractive editor Year Myopic patients 2020 2.620 billion 2030 3.361 billion 2040 4.089 billion 2050 4.758 billion " A more practical tactic is to focus on preventative things to minimize the chance of myopic patients [becoming] highly myopic, and especially the prevention of myopia-related complications. " –Zheng Wang, MD Refractive editor's corner of the world

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