> why is the text color set slightly off black Because pure black causes eye strain. Dark gray on white is superior for long reading sessions when your paper is white. The contrast really hurts after a while if you do pure black on pure white. This is a known phenomenon. In fact, there's experimental evidence (https://www.nature.com/articles/s41598-018-28904-x) that this high contrast plays a hand in the onset of myopia, which in extreme forms is correlated with glaucoma and other vision disorders.
Reading and Myopia: Contrast Polarity Matters
Andrea C. Aleman, Min Wang, Frank Schaeffel
2018 · Scientific Reports
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From the abstract
AbstractIn myopia the eye grows too long, generating poorly focused retinal images when people try to look at a distance. Myopia is tightly linked to the educational status and is on the rise worldwide. It is still not clear which kind of visual experience stimulates eye growth in children and students when they study. We propose a new and perhaps unexpected reason. Work in animal models has shown that selective activation of ON or OFF pathways has also selective effects on eye growth. This is likely to be true also in humans. Using custom-developed software to process video frames of the visual environment in realtime we quantified relative ON and OFF stimulus strengths. We found that ON and OFF inputs were largely balanced in natural environments. However, black text on white paper heavily overstimulated retinal OFF pathways. Conversely, white text on black paper overstimulated ON pathways. Using optical coherence tomography (OCT) in young human subjects, we found that the choroid, the heavily perfused layer behind the retina in the eye, becomes about 16 µm thinner in only one hour when subjects read black text on white background but about 10 µm thicker when they read white text from black background. Studies both in animal models and in humans have shown that thinner choroids are associated with myopia development and thicker choroids with myopia inhibition. Therefore, reading white text from a black screen or tablet may be a way to inhibit myopia, while conventional black text on white background may stimulate myopia.
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9 selected excerpts · 9 total mentions
Nature says yes: „Therefore, reading white text from a black screen or tablet may be a way to inhibit myopia, while conventional black text on white background may stimulate myopia.“ https://www.nature.com/articles/s41598-018-28904-x
https://www.nature.com/articles/s41598-018-28904-x Proposes that white on black stimulates a pattern of expression in visual system that may contribute to myopia: > Using optical coherence tomography (OCT) in young human subjects, we found that the choroid, the heavily perfused layer behind the retina in the eye, becomes about 16 µm thinner in only one hour when subjects read black text on white background but about 10 µm thicker when they read white text from black background. Studies both in animal models and in humans have shown that thinner choroids are associated with myopia development and thicker choroids with myopia inhibition. Therefore, reading white text from a black screen or tablet may be a way to inhibit myopia, while conventional black text on white background may stimulate myopia.
This article suggests that dark mode maybe protective against myopia while bright mode may induce myopia. https://www.nature.com/articles/s41598-018-28904-x
"Reading and Myopia: Contrast Polarity Matters" - https://www.nature.com/articles/s41598-018-28904-x : "reading white text from a black screen or tablet may be a way to inhibit myopia, while conventional black text on white background may stimulate myopia"
Also from the linked Nielson Norman Group article: > On the flip side, long-term reading in light mode may be associated with myopia. https://www.nngroup.com/articles/dark-mode/ https://www.nature.com/articles/s41598-018-28904-x
The blog post links an article by a usability research group: https://www.nngroup.com/articles/dark-mode/ That article mentions a study suggesting that light-mode screen viewing can contribute to myopia. I was very surprised by this. The study is here: https://www.nature.com/articles/s41598-018-28904-x I also found a few things that make me want to consider the findings seriously. The authors are well-known; Schaeffer (corresponding) has an h-index of 50. The study is also cited by a review on myopia from 2019, which notes (original study is [112]): >A recent hypothesis is that the problem may be associated with the predominant use of black text on white background [112].…
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This hypothesis proposes that the problem lies in the balance of stimulation of ON and OFF visual pathways, with natural scenes leading to balanced stimulation, with black text on white heavily overstimulating OFF pathways. Given that ON-bipolar pathways stimulate release of dopamine from amacrine cells [113], and dopamine agonists can inhibit axial elongation in animal models [114, 115], this is a promising link. https://link.springer.com/chapter/10.1007/978-981-13-8491-2_... Ironically, I think I'll be switching devices to dark mode a lot more having found this blog post. But as with any new scientific hypothesis, this one will probably evolve over the coming years.
The actual mechanism might be something like that! Nearsightedness is often caused by the eyeball developing to be too long. It’s actually dramatically increased in some places in Asia, where 90% of schoolkids can be nearsighted. [1] There’s a lot of research pointing towards biological processes involving contrast (which is probably a decent proxy for focus) being involved in eye development, with maybe different visual stimuli (due to more time spent indoors) being a potential cause of the increased myopia rates because it doesn’t activate the specific mechanism in the right way. [2] [3] [1] http://healthland.time.com/2012/05/07/why-up-to-90-of-asian-... [2] https://www.sciencedirect.com/science/article/pii/S004269891... [3] https://www.nature.com/articles/s41598-018-28904-x
Black text on white background may lead to myopia and white text on black background may be preventive. https://www.nature.com/articles/s41598-018-28904-x
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