"Given that younger children were assigned fewer online learning tasks than older children, it is unlikely that rapidly progressing myopia in younger children was caused by more screen time or homework that required close vision," e.g. The research team played video games and wrote in JAMA Ophthalmology. The most likely explanation is the lack of exposure to outside light.
As the editors of the Erasmus University Medical Center in the Netherlands suggest, "young children may be more sensitive to environmental triggers of myopia." A previous ophthalmological study conducted among children in Sydney also found that only the youngest who became myopic had spent more time in jobs that required close-ups rather than being in daylight.
Although many people have long believed that excessive reading promotes myopia in children, the current idea is that excessive indoor exposure has greater consequences and may better explain possible links between work that requires close-up photography or screen time and myopia.
Neil M. Bressler, an ophthalmologist with the Johns Hopkins Medical Institutions, says the high intensity of the external light has a significant impact on the shape of the eye, which in turn affects the ability to see images clearly.
In order to focus, the light rays must converge in an image on the retina. In myopic eyes, convergence occurs in front of the retina and a corrective lens is required to redirect incident rays so that distant objects are in focus.
Most children are easily born hyperopic. Your eyes are shaped like a partially deflated balloon, causing the images to converge behind the retina. As they grow, their eyes elongate into a ball so that the images can converge directly on the retina. However, if the elongation doesn't stop at some point, the eyes will become more oval and the images will converge in front of the retina, which is the definition of myopia. According to Bressler, outside light stimulates the release of dopamine, which can slow down the lengthening of the eye.
Although myopia is increasing worldwide, the epidemic is raging in East and Southeast Asia, where 80 to 90 percent of students are already nearsighted.