Specialized Spectacles Slow Myopia During Lockdown
Specially designed spectacles can slow the progression of myopia, even during the lockdowns mandated by the COVID-19 pandemic, researchers say.
Myopia progressed 46% more slowly in children prescribed defocus incorporated multiple segments (DIMS) lenses than in children prescribed standard prescription spectacles during 12 months when the children attended school at a distance, said Henry Chan, PhD, an associate professor of optometry at the Hong Kong Polytechnic University in Hong Kong.
“So that means the DIMS lens can be effective in this confined environment,” Chan told Medscape Medical News. He and his colleagues published the finding in JAMA Network Open.
The prevalence of myopia has been increasing around the world, particularly in East Asia. By some estimates, half the people in the world will have myopia by 2050, increasing their risk of sight-threatening diseases, such as glaucoma and retinal degeneration.
Previous research has shown correlations between myopia and time spent on near work and between myopia and time spent indoors. Several studies documented an acceleration in myopia progression when children spent more time indoors using devices for remote learning during lockdowns to prevent transmission of COVID-19.
Two treatments are now in use to slow the progression of myopia: atropine eyedrops and a positive powered lenses that casts a focal plane in front of the retina, slowing the eye’s axial growth.
Contact lenses using defocus have long been in use, but contact lenses can be difficult for small children to manage. So Chan’s colleagues at the Hong Kong Polytechnic University used the same principle in designing the DIMS spectacles. “We cannot say it is the most effective, but at least it is the most convenient, because it is just a spectacle,” Chan said. The lenses of the DIMS incorporate 3.50 D myopic defocus with multiple lenslets at the peripheral field.
A double masked and randomized clinical trial showed that the DIMS lens could slow the progression of myopia. The lens is now available in Hong Kong, the United Kingdom, Singapore, Europe, China, Taiwan, Malaysia, South Korea, Canada, Australia, and South Africa, said Chan. However, the US Food and Drug Administration has not approved it.
Separate studies found that atropine was much less effective than usual during the COVID-19 lockdowns. So Chan and his colleagues wanted to know if the same was true of the DIMS lenses.
Since no one had anticipated the COVID-19 lockdown, the researchers couldn’t plan a study dividing subjects into a control arm and a treatment arm. In addition, finding children to serve as controls has become difficult in Hong Kong because most parents want their children to be treated for myopia.
So the researchers compared 115 children who had been newly prescribed DIMS lenses as part of a charitable project to 56 children who wore single-vision lenses as controls in a previous trial.
The two groups didn’t match perfectly. Participants in the single-vision lens group had a mean age of 10.8 years, while those in the DIMS group had a mean age of 10.3.
Also, the children in the single-vision lens group had milder myopia on average, a mean spherical equivalent refraction (SER) of -2.99 D vs -4.02 D for the DIMS group.
Since the studies had begun at different times, the researchers only looked at evaluations of the subjects from June 2019 onward, treating this as the baseline.
The Hong Kong government suspended in-person school activities from February 2020 to May 2021. Since some participants had more visits before the lockdown than others, the researchers also compared those who had more than the median time in lockdown to those who had less.
Myopia progression in the children in this study on average accelerated about one third faster during the lockdown than in previous studies of children who were not locked down.
And the more time they spent locked down, the faster their myopia progressed. It progressed by a mean of -0.54 D in SER and 0.29 mm in axial length in those children who spent more time locked down vs -0.34 D in SER and 0.20 mm in axial length in those children who spent less time locked down (P = .001).
But the DIMS lenses appeared to help. After adjusting for covariates, the researchers found that the axial length increased 0.19 mm in the children wearing the DIMS lenses, but 0.30 mm in those wearing the single-vision lenses (P = .001).
Likewise, SER changed by -0.31 D in those wearing the DIMS lenses vs -0.57 D wearing the single-vision lenses.
The findings came as no surprise to Jeffrey Cooper, OD, a professor emeritus at the State University of New York, College of Optometry in New York City, who now treats children with myopia in private practice. He has closely followed the research into the DIMS lenses and wishes he could prescribe them to his patients. “It would be important to slow the progression of myopia in the United States to have these tools,” he told Medscape Medical News.
He was not concerned that the DIMS population in this study was younger because previous research has shown that DIMS is more effective in older children. “The fact that they slow the pattern, that’s what’s clinically important,” he said. “Clinicians go with risk against benefit. There is very little risk, and it can make a major difference to someone’s life.”
Chan and Cooper reported no relevant financial relationships.
JAMA Netw Open. 2022;5:e2143781. Full text
Laird Harrison writes about science, health, and culture. His work has appeared in magazines, newspapers, on public radio, and on websites. He is at work on a novel about alternate realities in physics. Harrison teaches writing at the Writers Grotto. Visit him at lairdharrison.com or follow him on Twitter: @LairdH.
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