Researchers have discovered a gene that causes myopia in people who spend at least an hour each day in childhood reading or doing other "near work."
Using a database of approximately 14,000 people, the researchers found that those with a certain variant of the gene - called APLP2 - were five times more likely to develop myopia in their teenage years if they had read an hour or more each day in their childhood.
Those who carried the APLP2 risk variant but spent less time reading had no additional risk of developing myopia.
"This is the first known evidence of gene-environment interaction in myopia," said the study lead investigator Andrei Tkatchenko from Columbia University Medical Centre in the US.
The researchers believe that the gene variant may increase the amount of APLP2 protein produced in the eye, which in turn may cause the eye to undergo excessive elongation.
They found that mice exposed to a visual environment that mimics reading were less likely to develop myopia when little APLP2 protein was present in the eye.
"By reducing the level of APLP2 in the eye, you can reduce susceptibility to environmentally induced myopia. This gives us an opportunity to develop a therapy to prevent myopia in everyone, regardless of the APLP2 variant they carry," Tkatchenko pointed out.
Developing such a therapy, however, could take years, as researchers don't yet know how APLP2 levels could be reduced in people.
The research was published in the journal PLOS Genetics.
