In a new study, researchers uncovered five genetic variants that enhance the likelihood of becoming nearsighted as children grow older.
These findings were published in the open-access journal PLOS Genetics by a team led by Jeremy Guggenheim of Cardiff University in the United Kingdom
Nearsightedness is linked to various eye problems, making it a primary cause of irreversible visual impairment in the elderly. People frequently acquire nearsightedness as children, and the disease appears to be caused by genetics, insufficient outdoor time, and many years of education. More than 450 genetic variations have been linked to an elevated risk of nearsightedness in studies.
However, few have been proven to raise risk specifically in those with related lifestyle variables.
In the new study, researchers used genetic and health data from more than 340,000 participants with European ancestry. They performed a genome-wide study to identify genetic variants that make people more susceptible to becoming nearsighted in combination with intensive schooling.
The study yielded five genetic variants that progressively increased the risk of becoming nearsighted for individuals, the more time they spent in school -- especially for people who had attained education at the university level. Three of these variants were previously unknown, while two were found in studies of East Asian cohorts, where about 80% of children become nearsighted. For comparison, about 30 per cent of children develop nearsightedness in the West. The researchers said that these findings provide new insights into the biological pathways that cause nearsightedness, but more research is needed to understand how those pathways interact with lifestyle factors to cause the condition.
Guggenheim added, "As well as requiring the need for glasses or contact lenses, myopia is a leading cause of uncorrectable visual impairment. Building on our previous research linking education and myopia, the new study identifies 5 genes associated with myopia development whose effects are amplified by additional years spent in education."
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