What Causes Myopia (Nearsightedness)?
Nature More Than Nurture? Genetics More Important Than Environment in Becoming Nearsighted?
Previous studies have suggested that there is a strong genetic component to why children become nearsighted as they grow into adulthood. A study from 2003, for example, suggested that genes are the main factor in determining who developes nearsightedness (myopia). This study looked at 388 8th grade children. The results showed that the higher the number of parents that have myopia, the greater the chance the child will become nearsighted, although the researchers were quick to point out that even having both parents being nearsighted does not guarantee the child will be nearsighted. Environmental factors did have a small role in determining who would become nearsighted in this study. Interestingly, in this study, nearsighted children performed higher overall than their non-nearsighted peers on reading and language skills testing.
Nurture More Than Nature? Environment More Important Than Genetics in Becoming Nearsighted?
Other studies have suggested that environmental factors are most responsible for determining which children will develop nearsightedness as they mature into adults. A landmark study from Taiwan showed that children who were required to spend recess outdoors in school were less likely to develop myopia than those who stayed indoors. This has led to speculation whether this is a direct effect of sunlight, physical activity, or even Vitamin D levels from sunlight.
A New Study Links Low Physical Activity and Screen Device Time to Nearsightedness
A new study adds support to theory that environmental factors play a large role in causing nearsightedness (myopia) to develop. This European study, conducted in Denmark, looked at 1,443 16-17 year old adolescent children, 45% boys and 55% girls, and found that those children who were physically active less than 3 hours a week had a doubling of their chances of developing nearsightedness! Those who used computer screen devices more than 6 hours per day also doubled their chances of developing nearsightedness. Unfortunately, it seems societal trends are toward less physical activity and greater time in front of computer screens and phone screens.
An Epidemic of Nearsightedness?
In 2000, 23% of the world’s population was nearsighted. By 2050, it is expected that 50% of the world’s population will be myopic. Given that the genetics of the human of the human population likely will not have changed in that time, this suggests that the enviromental factors of a less active, more computer screen oriented, more indoors world likely is the cause of so much nearsightedness. The good news, of course, is that with the latest generation of customized wavefront LASIK and customized wavefront PRK, we have outstanding ways to treat this growing epidemic of nearsightedness.
