https://www.scientificamerican.com/a...ghted-by-2050/By 2050, according to a new report from the Brien Holden Vision Institute in Australia, almost half the world will be nearsighted and require some form of corrective lens, up from a quarter of the global population in 2000.
Smartphones and technology are likely a contributing factor. However, the myopia rise in East Asia started in 1920s/1930s. Myopia prevalence among some east Asia demographics is 90%. Additionally, scholarly research did not start taking off until the 1950s/1960s. One of the leading theories is genetics and lack of outdoor time. If a population is 90% myopic, that would tell me some people have a gene that prevents whereas the majority do not.
An under researched area involves the extraoccular muscles. One recent study found that in high myopes, the extraocular muscles are thicker. With this knowledge, I pose the question: as people grow taller, do these extraoccular muscles grow thicker than needed and cause sclera thinning which promotes axial elongation?
The other side of this is depending on the gaze, axial length either lengthens, shortens, or doesn’t change. https://www.researchgate.net/figure/...fig2_230733472
Inferno nasal, inferior, supero-temperal and superior gazes show axial elongation. Supero-nasal shows axial shortening. Axial length also increases with nearwork associated accommodation. When reading while sitting, your head is at an angle and you are reading with a downward gaze. So could our reading/studying habits be the biggest factor. Simply angle a desk at 15% to reduce the downward gaze?
The other factor I’m interested in is lighting. If you look at a spectrum analysis of daylight, there are no peaks or valleys. Fluorescent lighting has dramatic peaks and valleys. Leds are slightly better but still no where close to day light. A lot of studies point to the overall brightness, but some studies have shown that lower Kelvin lights arrest axial elongation.
https://www.researchgate.net/figure/...fig1_312320039
incandescent Lighting started to fall out of favor during WW2 and by 1951, Fluorescent lighting produced more light than incandescent. Studies on myopia started to grow during the late 50s and have taken off exponentially. Seems like that angle needs to be explored more as incandescent lights are red heavy whereas fluorescent and led lighting have many peak and valleys. It has been explored in animal studies with conflicting results. Steady blue light can induce hyperopia whereas flashing blue can induce myopia. Some study’s have found red light therapy beneficial (gives some credence to red heavy incandescent.
1 more edit: myopia prevalence in Asia took off in the 50s which corresponds with fluorescent lighting. My theory on this is that Asians are much more more prone to axial elongation signaled by the wavelengths of fluorescent lighting. Also, the power frequency distribution could be a factor. Asia distributes power at 50 hz whereas the US distributes at 60hz.
Most interesting to me is there is a correlation of wealth and myopia which points to a technology related aspect. Wealth individuals can afford the latest lighting technology.
So my question is what do you all think is driving the increase in nearsightedness? With the onset of the myopia epidemic in Asia that predates some technological advances, I don’t believe it’s simply close up work on phones/computers. My theory it is a combination of nearwork, light wavelengths, and human growth patterns.
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Originally Posted by chuckman
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