Why do smart people wear glasses? Myopia is a consequence of intelligence

Relationship between educational level, intelligence and myopia checked
It is not unusual for smart people to wear glasses. Is that a subjective feeling or is there a plausible explanation? Scientists of the Mainz University Medical Center have also asked themselves this question and examined the connection between the occurrence of myopia and cognitive abilities. The effects of the intelligence on the eyesight are therefore given only indirectly - namely on the level of education.

Although intelligence in itself does not affect the development of myopia, the higher the level of education, the greater the likelihood of having to rely on glasses. The research team of the Mainz University Medical Center comes to this conclusion in the context of the "Myopia and Cognitive Performance: Results from the Gutenberg Health Study". The study results were published in the journal "Investigative Ophthalmology & Visual Science".

Does a human's intelligence affect the risk of myopia? Researchers say only about the detour of education time. (Image: Robert Przybysz / fotolia.com)

Myopia is the most common eye disease
Myopia is by far the most common eye disease, with severe myopia also being a major cause of visual impairment, reports the Johannes Gutenberg University Mainz (JGU). In addition, myopia is "closely associated with an increased risk of suffering from sequelae such as retinal detachment, macular degeneration, premature cataracts and glaucoma." Knowing the causes of the disease plays a key role in the early diagnosis and thus also for the treatment. Because in the early stages, myopia can be treated well, if not cure.

Are short-sighted not only educated, but also more intelligent?
According to Professor dr. Norbert Pfeiffer, director of the Department of Ophthalmology and Polyclinic of the Mainz University Medical Center, was already aware of previous studies, "that a high level of education is often associated with the development of myopia." In the current study under the joint leadership of Prof. Pfeiffer, Professor Dr. med. Alireza Mirshahi, Director of the Bonner Augenklinik Dardenne, and Professor Josef Unterrainer, Head of Medical Psychology and Medical Sociology of the University of Freiburg, scientists have now investigated whether not only the level of education but also the intelligence has an impact on the development of myopia.

Cognitive abilities and eyesight checked
For their investigation, the researchers used the data from the Gutenberg Health Study of the Mainz University Medical Center. This is one of the largest studies in the field of population-based research worldwide, according to the JGU Communication. In the subcohort, the data of around 4,000 persons between the ages of 40 and 79 were examined. The cognitive abilities were evaluated using the so-called Tower of London (TOL) tests, which measures in 20 minutes the ability to logically think, plan and solve problems. In addition, the researchers controlled the eyesight of the subjects, according to study definition from a strength of less than or equal to 0.5 diopters, myopia was present.

Apparent connection between myopia and intelligence
In the tests, the "participants with a myopia score a mean score of 14", while "the non-short-sighted peer group score only 12.9," according to the JGU statement. In addition, it has been shown that with increasing dioptric value, the result in the TOL test also improved. "So the short-sighted participants with more than six diopters reached an average value of 14.6," reports the JGU. At first, therefore, there seemed to be a clear connection between intelligence and myopia.

Duration of education is the decisive influencing factor
"On its own, cognitive performance, and therefore intelligence, is related to the occurrence of myopia"; the scientists report. However, this apparent relationship between myopia and better performance in the TOL test has resolved when the influence of the number of years of education has been taken into account. The researchers found that the number of years of education is more directly related to myopia than cognitive performance. The intelligence is connected only by the influence of the degree of education with a myopia. "The educational level of a person and not his intelligence is primarily crucial for the development of myopia," the scientists report. In the case of two equally intelligent people, the one who is likely to be short-sighted and more visually impaired is likely to go to school longer and to have a higher school diploma.

Professor Pfeiffer concludes that the current study further emphasizes the importance of education in the context of myopia. Now it has to be clarified how this connection arises. In future investigations, therefore, to investigate, for example, the impact of working on the screen or the use of smartphones, the study author continues. (Fp)