October 2016

 

REFRACTIVE

 

Myopia growth will have a domino effect worldwide


by Vanessa Caceres EyeWorld Contributing Writer

 
   
Glasses

Eyecare experts call for global campaign per myopia study projections

Staggering.” “Frightening.” “Should be a five-alarm alert.” Those are just some of the reactions to a study published earlier this year that suggests almost half of the world population will have myopia by the year 2050—and that nearly 1 billion people will have high myopia. That would be a seven-fold increase in high myopia compared with the year 2000.1

Those predictions were from the systematic review and meta-analysis “Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050,” published in the June issue of Ophthalmology.

The numbers were a surprise even for the study authors. “We expected an increase, but we did not think that the prevalence will reach 50%,” said study author Kovin Naidoo, PhD, CEO of Brien Holden Vision Institute, University of New South Wales, Sydney, Australia.

The study’s finding regarding the prevalence of high myopia is especially important because this subset of the population is at a greater risk for vision impairment and blindness from conditions such as glaucoma, cataracts, retinal detachment, and myopic macular degeneration, Prof. Naidoo said.

The impact of uncorrected distance refractive error—often caused by myopia—is estimated to be $202 billion annually, according to the authors.

Myopia experts from around the globe were taken aback by the results.

“While it is well-known that the prevalence rates of myopia were increasing in almost all populations globally, the sheer scale and magnitude of the problem is still surprising. However, their study methodology is strong and represents the best data we have to date,” said Donald Tan, FRCSE, Arthur Lim Professor in Ophthalmology, ophthalmology and visual sciences academic clinical program, Duke-NUS Graduate Medical School, and Singapore National Eye Centre, Singapore.

“Assuming a constant rate of myopic macular degeneration, this would catapult myopia up the ranks as a leading cause of permanent worldwide blindness,” said Yasha Modi, MD, assistant professor, Department of Ophthalmology, NYU Langone Medical Center, New York. “This study was a tremendous undertaking with a model that should be a five-alarm alert for policy makers in health and development,” said Janet Leasher, OD, professor and director of community outreach, Nova Southeastern University, College of Optometry, Fort Lauderdale, Florida.

Causes and implications

Environmental factors, such as lifestyle changes that include decreased time outdoors and increased near work activities, are likely a big cause of the upswing in myopia, according to study authors. “Among environmental factors, so-called high-pressure educational systems, especially at very young ages in countries such as Singapore, Korea, Taiwan, and China, may be a causative lifestyle change, as may the excessive use of near electronic devices,” they wrote. Although genetic predisposition may play a role, it cannot fully explain the trend, they added. Catching myopia early in life may also be an issue. In countries like the U.S., state-by-state variations in childhood vision screening requirements have likely allowed for increasing levels of myopia to go undetected as children and teenagers progress through school, Dr. Modi said.

The prevalence of refractive error in countries like the U.S. is sometimes taken for granted because it is so common, even in school-aged children, Dr. Leasher said. However, not all insurance covers routine eyecare—a fact that works against ensuring everyone has good visual health, she thinks. The projections should have a large implication on eyecare planning, Prof. Naidoo said. “There will be many more people in the world who will require spectacle correction who may not be able to afford it or access it in the future,” he said. There also may be lost productivity when people cannot see to work or study, Prof. Naidoo added. Governments and organizations should prepare for the added financial burden of providing eyecare services as well as for optical correction and surgeries for complications such as retinal detachment, Dr. Tan said. Certain developing areas of the world where myopia is on the rise will require better trained eyecare professionals, Dr. Leasher said. Ophthalmic-focused companies and providers must gear up for increased demands in products such as eyeglasses, contact lenses, and refractive surgery, said Roy S. Chuck, MD, PhD, chairman, Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Montefiore Health System, Bronx, New York.

The discussion of myopia projections is timely as the American Academy of Ophthalmology’s Preferred Practice Pattern (PPP) for Refractive Management and Therapy is being updated for publication in 2017, said Dr. Chuck, who chairs the panel and is part of the PPP governing committee.

Working ahead

Some parts of the world, like Asia, have recognized the epidemic and have begun to implement myopia control. This includes the use of contact lens, orthokeratology, spectacles, low-dose atropine, and increased time outdoors, Prof. Naidoo said. These same countries even have used media campaigns to encourage children to spend more time outdoors and to reduce screen time. Leaders at Brien Holden Vision Institute are developing extended depth of focus lenses to reduce the stimulus to eye growth by providing a focused retinal image across the whole retina, Prof. Naidoo said. At the Singapore National Eye Centre with Dr. Tan, low-dose (0.01%) atropine drops are used in children with progressive myopia. Singapore began examining its myopia problem 10 years ago, Dr. Tan said. Messages are sent to children and schools on how to maintain good eyecare habits by increasing outdoor activities, reducing near work, and getting regular eye checks. Dr. Tan and fellow researchers are starting new low-dose atropine trials that will treat younger children, at about 5 years old. “Low-dose atropine drops have now been proven to be able to reduce myopia progression in children, both effectively and safety, and other myopia control approaches such as peripheral defocus contact lenses and some spectacles may also be showing promise,” Dr. Tan said.

Regarding various myopia-targeted strategies, there are still questions regarding when and which therapy to start, treatment duration, when to stop treatment, and the extent of rebound myopia with cessation of therapy, Dr. Modi said. A review that compared 16 myopia control interventions found that atropine, pirenzepine, and progressive addition spectacle lenses were effective for targeting refraction.2 For targeting axial length, atropine, orthokeratology, peripheral defocus modifying contact lenses, pirenzepine, and progressive addition spectacle lenses worked best. Researchers found the most effective interventions overall were muscarinic antagonists such as atropine and pirenzepine. Still, a global campaign to address the issue is needed, Prof. Naidoo said. “Given the short-term approach of most governments, this is a difficult task. We will need to have an advocacy campaign in eyecare to really make a difference,” he said.

Slowing the rate of myopia with the use of optical and therapeutic strategies can be effective and should be part of a public health strategy to reduce the risk for high myopia and future vision impairment and blindness, Prof. Naidoo said. Eyecare practitioners also must work together to plan comprehensive eye services to manage and prevent myopic-related ocular complications, said Sally Dillehay, OD, chief medical officer and vice president, regulatory and clinical affairs, Visioneering Technologies, Alpharetta, Georgia. “We need to start looking at children who are 6 years old and who are still +0.75 D hyperopic but who are predicted to go on to become myopic,” she said. If practitioners can keep a –1.00 D myopic child from progressing above –3.00 D, the risks for myopic maculopathy, retinal detachment, and posterior subcapsular cataracts are lowered, she said.

“The old adage that people don’t die from a simple lack of good vision and therefore vision is not a priority is obsolete,” Dr. Leasher said. “Without being too alarmist, it’s time to stop ignoring refractive error as a non-communicable important health condition.”

References

1. Holden BA, et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology. 2016;123:1036–42.

2. Huang J, et al. Efficacy comparison of 16 interventions for myopia control in children: A network meta-analysis. Ophthalmology. 2016;123:697–708.

Editors’ note: Dr. Dillehay has financial interests with Visioneering Technologies. Prof. Naidoo has financial interests with Brien Holden Vision Institute. Dr. Tan has financial interests with Eye-Lens Pte Ltd (Singapore). Drs. Chuck, Leasher, and Modi have no financial interests related to their comments.

Contact information

Chuck
: lmarkens@montefiore.org
Dillehay: sdillehay@vtivision.com
Leasher: leasher@nova.edu
Modi: Annie.Harris@nyumc.org
Naidoo: k.naidoo@brienholdenvision.org
Tan: donald.tan.t.h@singhealth.com.sg

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