First-born children are more likely to be nearsighted
According to a study published in JAMA Opthamology, first-born children are more likely to be nearsighted than their younger siblings, and education investment might have something to do with it.
Research lead by Dr Jeremy A. Gugenhenheim of Cardiff University, UK sought to determine whether there is a correlation between this phenomenon and increased exposure to environments that have been known to pre-dispose children to near-sightedness, also known as myopia, such as time spent outdoors or reading and writing.
They studied 89,000 UK participants aged 40 to 69 years, all of which had no history of eye disorders. From this examination, first-born individuals were found to be 10 per cent more likely to be myopic and 20 per cent more likely to have high myopia.
"Our findings that statistical adjustment for indices of educational exposure partially attenuated the magnitude of the association between birth order and myopia, and completely removed the evidence for a dose-response relationship, therefore support the idea that reduced parental investment in children's education for offspring of later birth order contributed to the observed birth order vs. myopia association and produced the observed dose-response relationship,” researchers explained.
In other words, the tendency for parents to invest more in their first children in areas such as education may be a cause of increased near-sightedness amongst first-borns.