The Future Looks Bright but Blurry
Nearsightedness is on the Rise | June 28, 2022 | Sarah Singh
Odds are, no matter where you are in the world, you know someone with myopia (aka nearsightedness). It is estimated that over 20% of the global population currently have myopia. What may be surprising though, is that in the next generation, that number will more than double. It’s expected that 50% of the global population will have myopia by the year 2050.
People with myopia can see near objects, like books, tablets, and computers clearly, but their distance vision is blurred. Glasses, contact lenses, or refractive surgery are required to see clearly at all distances. Myopia causes eye health problems, too. People with myopia are far more likely to experience glaucoma, cataracts, retinal detachment, and macular degeneration, than people without myopia.
Why is myopia increasing?
Myopia typically develops during childhood school-age years, although some studies suggest that myopia prevalence is increasing even in preschool. Susceptibility to myopia is determined by a combination of genetics and environmental factors. For example, children who have one or more myopic parents are more likely to become myopic themselves. However, these rapid changes in prevalence strongly suggest that our visual environment is largely responsible for this sharp increase in myopia. Spending time outdoors is the only factor that has been shown to be effective at delaying or preventing the onset of myopia. If we consider the visual experience of most school-age children today, there is an emphasis on academic performance, which is accompanied by lots of homework; so much entertainment centers on electronic devices; and safety concerns often necessitate adult supervision for outdoor play, all of which severely limit outdoor time at an age when it is most critical for myopia prevention.
What can we do about it?
For children who are not yet myopic, spending time outdoors is currently the only factor known to prevent or delay myopia. This was shown in a clever study done in a suburban area of Taiwan. Researchers recruited two very similar elementary schools to participate in the study, in which one school was assigned to the treatment group and one school was assigned to the control group. The “treatment” consisted of requiring children to go outside for outdoor activities during recess, while the control group had no such requirement. It turned out that these outdoor activities during the school day were protective against the onset of new myopia. In the control school, 18% of children developed myopia during the 1-year study period, while only 8% of children in the treatment school developed myopia. So, we all need to make an effort to get children outdoors!
Once a child develops myopia, there are several treatments that are effective at slowing the progression of myopia, meaning that these treatments help prevent it from becoming worse. Those include atropine eye drops, specialty contact lenses, and more recently, novel spectacle lenses, which will be described in a future post. However, these only work if a child already has myopia, and are most promising if started very soon after the initial diagnosis of myopia.
If you have a question related to children’s vision, let us know at bv.cure@berkeley.edu
References:
- Holden BA, Fricke TR, et al. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology 2016; 123: 1036-1042 (link)
- Wu PC, Tsai CL, et al. Outdoor Activity during Class Recess Reduces Myopia Onset and Progression in School Children. Ophthalmology 2013; 120:1080-1085 (link)