Myopia is one of the main causes of irreversible vision impairment in older people, but this visual disease associated with various eye disorders usually begins in childhood and seems to occur as a result of a combination of genetic factors. and school time, to which is added the fact that children do not spend enough time outdoors.
A group of scientists led by Jeremy Guggenheim, a professor at Cardiff University’s School of Optometry and Vision Sciences, has now identified five genetic variants that progressively increase a person’s risk of nearsightedness the longer they remain at school and spends more hours studying. Previous genetic studies have already found more than 450 genetic variants associated with an increased risk of being myopic, but few have been shown to specifically increase risk in individuals with the associated lifestyle factors.
Using genetic and health data from more than 340,000 people of European descent whose data had been collected in the UK Biobank, the researchers studied the entire genome to identify genetic variants that make people more likely to become myopic in combination with a intensive schooling. They thus found five genetic variants that progressively increased the risk of people becoming myopic as they spent more time in school, especially in the case of those who studied a university degree.
Educational and genetic factors that influence the risk of myopia
Three of these variants were not known, while the other two had been found in cohort studies from East Asia, where about 80% of children become myopic, while in the West about 30% of children they develop myopia. The researchers say the study results, which have been published in PLOS Genetics, provide new insights into the biological pathways that cause myopia, but acknowledge that further research is needed to understand how these pathways interact with lifestyle factors to trigger the disease.
“The new study identifies five genes associated with the development of myopia, the effects of which are magnified by additional years spent teaching”
Guggenheim has stated: “In addition to requiring the use of glasses or contact lenses, myopia is one of the leading causes of uncorrectable visual impairment. Building on our previous research linking education and myopia, the new study identifies 5 genes associated with the development of myopia whose effects are magnified by additional years spent teaching.”
Sergio Recalde Maestre, Researcher at the Laboratory of Experimental Ophthalmology of the University of Navarra School of Medicine, has given his opinion in statements to the Science Media Center Spain (SMC): “This large study, with more than 340,000 sequenced samples, is a very good analysis. carried out to see the interaction of genomics and the environment in a disease as important and prevalent as myopia. Many studies have shown the importance of changing habits that has led to an imbalance between the time spent doing activities outdoors and the time spent doing activities up close. This work “through analysis of the genome-wide association study shows five genetic variants that confer a progressively higher risk of myopia in people who spent more years in their education and, therefore, with time in near activities.”
The research, continues this expert, “extends in a very simple way the interaction of the educational level of the participants with respect to myopia. In a first phase of participants (88,000) diagnosed with their diopters, 25 genes with a certain association have been obtained depending on whether or not they have university studies. These same genes have been analyzed in a second phase of patients without diopters (252,000), but knowing the years of glasses use to confirm the association of the gene variants (risk alleles) and have obtained a very high significance in five of them (GJD2, RBFOX1, LAMA2, KCNQ5 and LRRC4C).” Ramón Gutiérrez, professor of Ophthalmology at the University of Murcia who did not participate in the study, points out that “Two of these variants are already known, the biological mechanism through which they could influence the growth of the eyeball has even been studied, and another three are contributions made in this work”.
This work is a confirmation of the results that were recently observed regarding the importance of genetic interaction with the environment in the silent pandemic that is currently myopia. The prevalence of this disease, especially in children, was already a serious problem in Asia for a few decades, but now it is affecting the world and genetic inheritance alone as a risk factor could not respond to this dramatic increase in the last years. It was clear that environmental factors, lifestyle (especially in the open air/close work imbalance) were also acting in a very powerful way and that this interaction of several genes that enhance elongation has been found, also in the Caucasian population. of the eye for being long periods of study is a great advance.
Having this knowledge “has to serve to make, in those people who present these genetic variants, a more exhaustive follow-up of the progression of their myopia during their studies. Also so that they take breaks into account during their study – the ‘20206’ rule: every 20 minutes of close-up activity, 20 seconds of rest looking at more than 6 meters – and so that they combine these with plenty of outdoor activities” , emphasizes Recalde.
.
