Exercising the eyes
A lack of exercise is particularly noticeable in children - including exercise for their eyes. Recent studies from the Netherlands and China show that as a result of COVID-19 restrictions, myopia has increased dramatically, especially in children. The phenomenon has been called “quarantine myopia”.
Data from more than 120,000 Chinese school children showed that kids between the ages of six and eight were up to three times more likely to have myopia in 2020 than children of their age in previous years. In this age group, visual acuity shifted by a substantial 0.3 diopters towards myopia.
This drastic deterioration of eyesight in young children is particularly frightening because being nearsighted (not being able to see objects that are farther away) is determined at an early age. Once someone is nearsighted, they stay that way. In most cases, nearsightedness begins in primary school and it increases as children grow up. The earlier it starts, the more severe it becomes. The grown eye does not shrink again.
If the eyeball grows too much between the ages of six and 10, it means the child has a harder time seeing objects farther in the distance. Severe nearsightedness also increases the risk of retinal detachment, cataracts due to high pressure inside the eye, or even blindness later in life.
The better the education, the worse the eyesight
According to the Brien Holden Vision Institute, by the middle of the century around five billion people, or roughly half of the world’s population, will be nearsighted. Especially in industrialized countries, the number of nearsighted people has risen rapidly in recent decades.
There is even a direct correlation between increased educational opportunities and poorer vision – the higher the level of education, the higher the risk of myopia.
“The increase is mainly due to very early and intensive use of PCs, smartphones and tablets, combined with increasingly shorter amounts of time spent outdoors during the day,” said Nicole Eter, Director of the Department of Ophthalmology at the University of Münster.
Asian countries have above-average rates of nearsighted children and adolescents. For example, after World War II, about 20-30% of 20-year-olds in Hong Kong, Taiwan and South Korea were nearsighted; today the figure is more than 80%. In China, four out of five young people are now nearsighted. In other Asian countries, the rate is as high as 95%. In Europe too, about half of young adults are nearsighted.
Distance and daylight help fight myopia
The risk of myopia can be reduced by not staring too long at an object in close range, regardless of whether it is a smartphone or an exciting book. The important factor is distance. The observer needs to look up regularly so that the gaze can wander into the distance.
The risk of myopia is reduced primarily by longer amounts of time spent outdoors, because daylight inhibits further growth of the eyeball. In enclosed rooms, the light intensity averages 300 to 500 lux (a measure of light levels), whereas on a bright summer day it can be around 100,000 lux outside. Studies from Scandinavia also show that myopia increases in the darker seasons, while it stagnates during brighter times of the year.
Blue light affects sleep
Excessive use of electronic media does not just lead to more nearsightedness. It can also irritate, tire and dry out children’s eyes. Constantly looking at screens also affects spatial awareness. Blurred vision or squinting can result from too much time spent on devices.
In addition, smartphone use in the evening may lead to sleep disorders.
“The high blue light content of the screens inhibits the release of the hormone melatonin, which makes you sleepy,” explained Eter.
Although many devices now have a night mode that reduces the blue light, we should stop looking at them around two hours before bedtime.
Eyes need rest and proper lighting
Parents should limit their children’s use of digital media, especially for the youngest age groups.
“From an ophthalmological point of view, PCs, smartphones and tablets are completely unsuitable for children up to the age of three,” said Bettina Wabbels from the Bonn University Eye Clinic. The eye expert recommends daily use of no more than thirty minutes for four- to six-year-olds.
“At primary school age, media time of a maximum of one hour per day would be acceptable from an ophthalmological point of view, and up to two hours per day from the age of about ten,” explained Wabbels.
However, her advice doesn’t just apply to children and adolescents. Adults’ eyes also need a break. So look up from the screen more often, let your eyes wander and spend more time outdoors.