"Put that book down! You'll ruin your eyes with too much reading," grandparents have been saying for centuries. And it turns out, they may have been onto something.
A new German study finds that nearsightedness may be linked to higher education levels and more years spent in school.
Published online this month in Ophthalmology, the journal of the American Academy of Ophthalmology, the research is the first population-based study to demonstrate that environmental factors may outweigh genetics in the development of myopia.
The antidote to the rise in myopia could be as simple as going outside more often.
"Since students appear to be at a higher risk of nearsightedness, it makes sense to encourage them to spend more time outdoors as a precaution," said Alireza Mirshahi, M.D., lead author of the study, perhaps unconsciously echoing advice from your grandmother.
While it has always been somewhat common, nearsightedness has become even more prevalent around the world in recent years and presents a growing global health and economic concern.
Severe nearsightedness is a major cause of visual impairment and is associated with greater risk of retinal detachment, myopic macular degeneration, premature cataracts and glaucoma. In the United States, nearsightedness now affects roughly 42% of the population.
Environmental factors that have been previously linked to myopia include near work (such as reading or using a computer), outdoor activity, living in urban versus rural areas and education.
To further analyze the association between myopia development and education, researchers at the University Medical Center in Mainz, Germany examined nearsightedness in 4,658 Germans ages 35 to 74, excluding anyone with cataracts or who had undergone refractive surgery. Results of their work, known as the Gutenberg Health Study, show that myopia appeared to become more prevalent as education level increased:
- 24% with no high school education or other training were nearsighted
- 35% of high school graduates and vocational school graduates were nearsighted
- 53% of university graduates were nearsighted
The researchers also found that people who spent more years in school proved to be more myopic, with nearsightedness worsening for each year of school. Furthermore, the researchers looked at the effect of 45 genetic markers, but found it a much weaker factor in the degree of nearsightedness compared to education level.