The Grapevine

Studying More May Increase Risk Of Needing Prescription Glasses

A new study from the United Kingdom shed light on the link between education and the risk of developing nearsightedness. It could potentially have important implications for educational practices, according to the research team.

The paper titled "Education and myopia: assessing the direction of causality by mendelian randomization" was published in the British Medical Journal (BMJ) on June 6. 

Nearsightedness, known as Myopia, is a condition in which nearer objects appear clear but distant objects appear blurry. It is considered a leading cause of visual impairment, affecting 30 to 50 percent of adults in the United States. "Myopia has been associated with higher levels of educational attainment for more than a century," said co-author Denize Atan, a consultant senior lecturer at the University of Bristol. 

Studies have been observational in nature since exposing children to different levels of education in clinical trials would be unethical. As a result, it remained unclear whether myopic children are more studious, or if increased exposure to education caused myopia, or if socioeconomic position led to both myopia and higher levels of education.

For the new study, researchers used a method called Mendelian randomization which can measure causal effect with the help of genes. It can also avoid some of the drawbacks of observational studies such as the effects of confounding factors.

They analyzed 44 genetic variants associated with myopia and 69 genetic variants associated with years of schooling for more than 67,700 people aged 40 to 69 years. The researchers found "strong evidence" that education was one of the drivers behind higher myopia rates. However, being predisposed to myopia did not have any noticeable effect on one's education.

They are yet to identify how exactly more time in education causes myopia. One of the potential factors may be light exposure, according to Atan, adding that natural light might have a protective effect according to clues from previous research

The significantly higher prevalence of myopia in Asia has been speculated to be due to the intense academic pressure encouraging indoor studying and reduced time spent outdoors. "Surprisingly, an association between time spent reading and myopia is less consistently shown across studies than the protective effect of time spent outdoors," Atan said. 

"This evidence suggests that it is poor light rather than reading per se that damages your eyes, and has been one of the main drivers for recent investment in bright light classrooms to protect against myopia in southeast Asia."

One limitation of the study was the use of data from the U.K. Biobank. The participants who contribute to this database are typically healthier, highly educated, and report fewer health problems compared to the rest of the population. But there was insufficient evidence that this could explain the findings.