Why are glasses associated with high intellect

How myopia, education and intelligence are related

Mainz - It has not yet been conclusively clarified whether myopia also has genetic causes. While there have been many studies on this question, the results often contradicted each other. It is clear, however, that certain environmental factors have a noticeable influence on the development of myopia. A correlation between level of education and myopia was also found. German scientists now wanted to get to the bottom of the question whether a connection between intelligence and myopia can be derived from this. Their result: There is actually a connection, but only an indirect one.

Myopia is the eye condition that affects most people - and the number is increasing. Since myopia can be treated well, if not cured, in its early stages, knowledge of the causes of the disease is of central importance. "We know from previous studies that a high level of education is often associated with the development of myopia," says Norbert Pfeiffer, lead author of the current study. But are nearsighted people not only more educated, but also more intelligent?

It depends on the years of education

The study superficially suggests that, viewed in isolation, cognitive performance, and thus intelligence, is actually related to the occurrence of myopia. When the scientists took all influencing factors into account, however, they found that the number of years of education is more directly and more strongly related to myopia than cognitive performance. This ability is associated with myopia only through the influence of the level of education. In other words, a person's level of education, and not their intelligence, is primarily decisive for the development of myopia. Of two equally intelligent people, the one who goes to school longer and has a high school diploma is more likely to be nearsighted and more ametropic.

For their study, the research team evaluated data obtained as part of the Gutenberg health study of the Mainz University Medical Center - one of the world's largest studies in the field of population-based research. The sub-cohort comprised around 4,000 people between the ages of 40 and 79 years. To measure cognitive skills, the researchers used the Tower of London (TOL) test. The 20-minute test measures the ability to think logically, plan and solve problems. In order to determine myopia, the scientists examined the refractive power of the eyes, i.e. how much the eye has to correct in order to see an image clearly.

The more myopic, the better the test result

The participants with a myopia achieved a value of 14 as an average result for the TOL test. The comparison group of the non-nearsighted achieved a value of only 12.9. It also showed that the higher the myopia value, the higher the TOL score. The severely short-sighted participants with more than six diopters achieved an average value of 14.6. However, this apparent association between myopia and better performance in the planning test dissolved when the researchers also considered the influence of the number of years of education.

"The current study further clarifies the importance of education in connection with myopia," explains Pfeiffer. "In further studies, we will examine the influence of close-up work on the screen or through the use of smartphones more closely." (red, November 12, 2016)