New Delhi, Aug. 18: Children who spend time outdoors during daylight hours appear to be protected from myopia, or nearsightedness, according to medical studies that eye doctors believe are strong enough for a take-home message.
Two new studies in Denmark and Taiwan have shown that daylight may prevent or curb the risk of myopia, a condition correctable by glasses, but whose severe forms may raise the risk of glaucoma or retinal detachment in adulthood.
“The evidence for this protective effect of daylight is mounting,” said Quresh Maskati, an eye doctor in Mumbai, who is also the president-elect of the All India Ophthalmological Society (AIOS). “India is blessed with sunlight and we should amalgamate this advisory into our practice,” Maskati, who was not associated with either study, told The Telegraph.
But Maskati and others in the AIOS have cautioned that the suggestions by some doctors that smartphones may cause eyesight problems in children are yet to be substantiated with hard evidence.
David Allamby, a leading laser eye surgeon in the UK has claimed that since the launch of smartphones in 1997, there has been a 35 per cent increase in patients with advancing myopia.
Research has shown that smartphone users hold their handsets only 18cm to 30cm away from their faces, compared with newspapers and books, which are held about 40cm away.
Martin Banks, a professor of vision science at the University of California, Berkeley, had in a study published in the Journal of Vision two years ago suggested that the demand on the eyes to focus on the screen while at the same time adjust to the distance of the content may account for visual discomfort linked to mobile devices.
“We’ve known for decades that prolonged near work may lead to small changes in power, but this cannot lead to any large change,” said Lalit Verma, a senior consultant with the Centre for Sight, New Delhi, and secretary of the AIOS. “And this effect resulting from the prolonged near work can come from books, newspapers, or anything, not only smartphones,” he added.
Maskati said a scientific meeting of the American Association for Paediatric Ophthamology held in Singapore last month had discussed the protective effect of daylight against myopia, but not the risk of smartphones.
The studies on daylight from Denmark and Taiwan were published in May this year in the journal Ophthalmology. In Taiwan, researchers observed that the new onset of myopia was “significantly lower” among children who spent their school recess time outdoors than among children who spent it indoors.
An independent study in Denmark has shown that progression of myopia appears to decrease in periods with longer days and increase in periods with shorter days. “Children should be encouraged to spend more time outside during the daytime,” the researchers from Denmark and China wrote in their study.
“Parents should encourage children to spend time outdoors daily. When that is impractical because of weather or other factors, the use of daylight-spectrum indoor lights should be considered a way to minimise (the risk of) myopia,” said Dongmei Cui, a Chinese researcher who led the study.