Economic development, education will lead to increase in myopia
ORLANDO, Fla. – The prevalence of myopia is estimated at 33% in the U.S., 40% in Europe and 80% in Asia, but an increase is expected to occur with economic development, urbanization and increased rates of education in the developing world, according to Donald O. Mutti, OD, PhD.
Mutti spoke here at the American Academy of Optometry meeting during a joint AAO-American Academy of Ophthalmology symposium on the global myopia burden.
He reviewed data on the prevalence of myopia in the U.S. dating back to 1928, when it was about 4%. Different studies cite different statistics, but, “if you compare studies across decades, I use 25% in the U.S. in 1975 and 33% in 2005,” Mutti said.
He also noted that where the criteria is set has a dramatic effect on the prevalence.
Mutti said Flitcroft and colleagues defined myopia as: “A condition in which the spherical equivalent objective refractive error is less than or equal to 0.50 D in either eye.”
“Asia has an amazingly high incidence of myopia,” he said. “In Taiwan, kids are becoming myopic at higher rates as they become older. It’s an 80% prevalence in later birth decades.”
He continued, “I will argue that we are not experiencing an epidemic of myopia in the U.S. as a developed country. In the developing world, we are getting an increase.”
Mutti said that some question whether the increase in myopia is caused by near work or less time outdoors.
“I put my money on education being about time indoors more than near work,” Mutti said.
“Pockets of resistance” exist, including a region of Ireland, Scandinavia and Australia, he said. He attributes the low prevalence in Australia to time outdoors and sun exposure, “but there’s not so much sunshine in Norway except for the long days in the summer. Maybe there’s something in the diet that’s magic about being Norwegian or Danish.”
Myopia is “a big deal,” Mutti said. “The increase in the growth of the eye stretches the globe. If it’s 26 mm or longer, it’s not good. Of those folks, they have a lifetime risk of 20% for vision impairment. The cutoff for pathological myopia is -6.00 D. An increase in vision impairment of sevenfold to 13-fold is predicted by 2050.”
In his conclusions, he noted, “We can expect to deal with the clinical and economic consequences of an increasing prevalence of myopia around the world.” – by Nancy Hemphill, ELS, FAAO
Flitcroft DI, et al. Invest Ophthalmol Vis Sci. 2019;doi.org/10.1167/iovs.18-25957.
Walline J, et al. Addressing the global myopia burden. Presented at: American Academy of Optometry meeting; Orlando, Fla.; October 22-27, 2019.
Disclosure: Mutti reports he is a consultant/advisor for Welch Allyn.