Using the 1971-1972 method, the estimated prevalence of myopia in persons aged 12 to 54 years was significantly higher in 1999-2004 than in 1971-1972 (41.6% vs 25.0%, respectively; P -2.0 diopters [D]: 17.5% vs 13.4%, respectively [P -7.9 D: 22.4% vs 11.4%, respectively [P
When using similar methods for each period, the prevalence of myopia in the United States appears to be substantially higher in 1999-2004 than 30 years earlier. Identifying modifiable risk factors for myopia could lead to the development of cost-effective interventional strategies.
Here are some tables:
Citation: Susan Vitale; Robert D. Sperduto; Frederick L. Ferris, III, Increased Prevalence of Myopia in the United States Between 1971-1972 and 1999-2004, Arch Ophthalmol. 2009;127(12):1632-1639.
I'm not claiming causation, but I have read that myopia in children is commoner the more light they have in their bedrooms at night.
@Monado: it has been observed that myopia is more common in children that do not spend time outdoors. The more light there is, the less myopic the children will be.
Monado: from the Wikipedia page on myopia:
Although one initial study indicated a strong association between myopia and nightlight exposure, recent research has found none.
It also gives several references.
Collateral damage from the Flynn Effect?
Myopia is associated with high insulin levels, so this makes sense.
The New Scientist run an interesting article about the causes behind myopia a few weeks ago. They reported some compelling very recent research which found a strong negative association between hours spent playing outdoors and myopia.
I wonder how much of this (like the autism "epidemic") is down to detection.
I'm severely myopic and knew it from a young age. However, in my rural community, there was no education for parents on vision care. I got my first pair of glasses at age 16, when I was old enough to sort it out for myself.
Parents these days seem to be better informed and vision care is much more available- even in such rural areas.
This would be a case where it might be more useful to use the myopia records at a single school. Take a small town elementary school where the population has been relatively stable over time and see whether myopia has gone up. Then repeat at a few other schools.