Firstborn Kids More Likely to be Nearsighted
The firstborn child in a family is more likely to develop nearsightedness, according to a new study published in _Jama Ophthalmology. _
Genetics is one of the main risk factors for the condition, as well as time spent outdoors and high amounts of “near work,” such as reading and writing.
Based on the results of prior research, scientists from Cardiff University in the UK believed high rates of nearsightedness may be due to a higher level of educational investment in firstborns. Previous studies have also shown that parents put more resources into their first children, including education, which could make for a more “myopia predisposing environment.”
Data was collected for more than 89,000 people from the UK Biobank, from ages 40 to 69, with no prior history of eye disorders. Firstborns of the group were shown to be 10 percent more likely to be myopic, and 20 percent more likely to have a more severe form of myopia. The team found these values grew stronger once adjusting for education exposure, which suggests that fewer educational resources provided younger siblings could be why they have a lesser chance of developing myopia.
Although this was a large study, the authors pointed out that a “causal relationship cannot be made based on observational evidence.”
The team also used self-reported data, and excluded for those who had cataracts, which left room for bias within the study. The study also did not look into time spent outside, which is one of the main risk factors for the disease.