Nearsightedness in School Students Often Goes Undetected
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The letters and numbers written on the classroom blackboard were blurred or road signs on their way to school only became legible much later than before – many nearsighted people use such examples to describe how they first noticed their poor vision. Non-congenital myopia indeed often develops between the age of eight and 14 years, which is why it is also referred to as “school myopia”. It occurs because the eyeball has grown slightly bigger, so inside the eye rays of light no longer come together on the retina but instead in front of it, which produces a blurred image. Under certain circumstances, school myopia can even worsen as youngsters reach early adulthood.
“One of the main signals that tells the body to inhibit the eyeball’s growth is bright light,” explains Professor Sarah Weigelt, head of the “Vision, Visual Impairments and Blindness” team at the Department of Rehabilitation Sciences. “Even with good lighting, we do not have more than 350 to 500 lux indoors, whereas outside it’s around 10,000 lux even on dull winter days. In contrast, near work, for example when we have to focus on something close up over a longer period, such as a computer screen or an exercise book, stimulates eyeball growth.” Scientists therefore assume that environmental factors can also play a role in the development of nearsightedness, alongside biological causes.
Large-scale screening in schools
Researchers have established that the number of nearsighted people worldwide has been rising for decades. In Southeast Asia, up to 90 percent of adolescents and young adults are affected. Europe is also seeing an increase, and according to researchers there are initial signs that nearsightedness might have increased at an even faster rate during the coronavirus pandemic. To create a scientific basis for possible preventive measures, Professor Weigelt and her team implemented large-scale screening at ten schools and examined around 1,500 school students at the limits of the age range in which school myopia usually develops. The study included children in the third and fourth grades at six primary schools and in grades eight to ten at one secondary school per type.
While an average of around 8% of the school students in the third and fourth grades were found to be nearsighted, the percentage increased significantly in the higher grades: from almost 12% in the eighth grade to over 21% in the ninth grade and even 25.7% in the tenth grade. This means that approximately one in four school students in the tenth grade was nearsighted. The results additionally show that girls are already affected more frequently than boys from the fourth grade onward and that this gender difference increases with age. According to the researchers, one possible contributing factor, for example, that could also play a role here, may be that the social environment of girls puts more of an emphasis on learning and near work than that of boys.
Undetected nearsightedness is widespread
“Our screening also revealed that nearsightedness had previously gone undetected in around half the affected children,” reports Professor Weigelt. “This is worrying, because if myopia is left uncorrected, it has a negative impact on their learning performance and consequently also on their career prospects, as well as potentially even leading to health complications later on.” Although some of the youngsters examined had already noticed that they could not see properly, they nevertheless told the researchers that they did not want to wear visual aids such as spectacles or contact lenses – primarily because they were worried about their appearance and how others would react. Accordingly, the starting point for future preventive measures could be schools and peer groups, for example in the shape of regular eye tests and educational programs tailored to the needs of young people.
The team also observed slight differences between the different types of schools: In primary schools with a low social index, uncorrected myopia was around 22% lower than in schools with a higher index. A school’s social index reflects the composition of its student body: the higher its index, the greater the school’s social challenges, for example due to child poverty in its catchment area. At the same time, the jump in the percentage of nearsighted pupils between the individual grades was most pronounced at the grammar school (“Gymnasium” in German) participating in the study. “We can conclude that the complex interrelationships between social index, school type and myopia ought to be examined further in larger studies,” says Professor Weigelt. “These too might deliver important clues for developing preventive measures so that school myopia can be detected and corrected at an early stage.”
The study by the “Vision, Visual Impairments and Blindness” team was published in a special issue of the journal “Frontiers in Medicine” dedicated to “Myopia in Childhood and Adolescence”.
Click here for the article in “Frontiers in Medicine”
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