Researchers warn of a new "epidemic" of myopia or myopia after observing sharp increases in the growing onset of myopia among late baby boomers.
Based on data collected from 107,442 participants in the UK's comprehensive Biobank program, people born in the late 1960s are 10 percent more likely to be nearsighted than people born three decades earlier.
The biggest jump was in people who experienced their vision changes later in life, although the number of serious cases doubled during the same period among those with child-onset myopia.
The condition is thought to be caused by a combination of genetic and environmental factors, including increased screen time - although the study also finds evidence that these are trends that can be changed with the right public health initiatives.
"It is now an urgent public health problem internationally, with a new 'epidemic' of myopia, characterized by increasing prevalence accompanied by a whole population shift in the distribution towards younger age at onset and greater severity," the researchers explain in their paper.
The oldest cohort covered by the Biobank survey was people born between 1939 and 1944: Here, 12.6 percent developed myopia in childhood and 7.4 percent developed it later in life. For the youngest cohort, born between 1965 and 1970, these numbers rose to 15.6 percent and 13.6 percent, respectively.
Overall, the proportion of those with myopia in the oldest and youngest cohorts increased from 20 percent to 29.2 percent, although most of the additional adult cases were mild. Although it does not tell the whole story - the highest percentage, 30.9 percent, was recorded for those born between 1955 and 1959 - it shows a worrying trend.
By digging further into the data, the researchers suggest several reasons for the leap: changes in the nutrition of diets in childhood, increases in the use of digital screens and shifts in teaching methods (more homework and less time spent outdoors, for example).
An increase in the number of people staying in education after the age of 18 may also be a factor, according to the research. This association between higher education (several years spent reading, revising, and graduating) and a higher risk of myopia has been previously noted in several previous studies.
"There has been a shift over time in the proportion of children who choose to stay in higher education and higher education and parallel teaching methods, widespread use of television and more recently the widespread use of electronic display devices and the expansion of such activities into leisure time, ”the researchers write.
As other studies around the world have shown, myopia is becoming a problem for more people earlier in life, while a higher proportion of people who develop myopia report more serious cases of eye disease.
However, the evidence presented here for a plateauing of myopia frequency among people born between 1955 and 1970 supports the idea that these trends can be stabilized or even reversed, according to the researchers.
For this to happen, further studies will be needed on how different influences affect the risk of myopia and how childhood rates (most likely determined by genetics) differ from adults (most likely influenced by environmental factors).
"A mixed research economy is needed to improve our understanding of modifiable risk factors across the life course and how to tackle them," the researchers conclude.
The research is published in PLOS ET.