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The study results showed that both visual acuity and the subjective visual fatigue were significantly affected by the color of light [4].

 

Images with excessive energy at medium spatial frequencies (Fernandez and Wilkins, 2008 Perception 37 1098-1113), or that have high color contrast and little or no luminance contrast (Wilkins et al, 2008 Perception 37 Supplement, 144-145) appear uncomfortable or aversive and can induce headaches in hypersensitive observers. Such stimuli are uncharacteristic of natural images [...] [5].

Melatonin concentrations after exposure to the blue-light goggle experimental condition were significantly reduced compared to the dark control and to the computer monitor only conditions. Although not statistically significant, the mean melatonin concentration after exposure to the computer monitor only was reduced slightly relative to the dark control condition [6].

 

All light is not equal: blue wavelengths are the most potent portion of the visible electromagnetic spectrum for circadian regulation. [...] evening use of amber lenses to block blue light might affect sleep quality. Mood is also affected by light and sleep; [...] At the end of the study, the amber lens group experienced significant (p < .001) improvement in sleep quality relative to the control group and positive affect (p = .005). Mood also improved significantly relative to controls [7].

The study results showed that both visual acuity and the subjective visual fatigue were significantly affected by the color of light [4].

 

Images with excessive energy at medium spatial frequencies (Fernandez and Wilkins, 2008 Perception 37 1098-1113), or that have high color contrast and little or no luminance contrast (Wilkins et al, 2008 Perception 37 Supplement, 144-145) appear uncomfortable or aversive and can induce headaches in hypersensitive observers. Such stimuli are uncharacteristic of natural images [...] [5].

Melatonin concentrations after exposure to the blue-light goggle experimental condition were significantly reduced compared to the dark control and to the computer monitor only conditions. Although not statistically significant, the mean melatonin concentration after exposure to the computer monitor only was reduced slightly relative to the dark control condition [6].

 

All light is not equal: blue wavelengths are the most potent portion of the visible electromagnetic spectrum for circadian regulation. [...] evening use of amber lenses to block blue light might affect sleep quality. Mood is also affected by light and sleep; [...] At the end of the study, the amber lens group experienced significant (p < .001) improvement in sleep quality relative to the control group and positive affect (p = .005). Mood also improved significantly relative to controls [7].

The study results showed that both visual acuity and the subjective visual fatigue were significantly affected by the color of light [4].

Images with excessive energy at medium spatial frequencies (Fernandez and Wilkins, 2008 Perception 37 1098-1113), or that have high color contrast and little or no luminance contrast (Wilkins et al, 2008 Perception 37 Supplement, 144-145) appear uncomfortable or aversive and can induce headaches in hypersensitive observers. Such stimuli are uncharacteristic of natural images [...] [5].

Melatonin concentrations after exposure to the blue-light goggle experimental condition were significantly reduced compared to the dark control and to the computer monitor only conditions. Although not statistically significant, the mean melatonin concentration after exposure to the computer monitor only was reduced slightly relative to the dark control condition [6].

All light is not equal: blue wavelengths are the most potent portion of the visible electromagnetic spectrum for circadian regulation. [...] evening use of amber lenses to block blue light might affect sleep quality. Mood is also affected by light and sleep; [...] At the end of the study, the amber lens group experienced significant (p < .001) improvement in sleep quality relative to the control group and positive affect (p = .005). Mood also improved significantly relative to controls [7].

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Cones SMJ2 E.svg http://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Cones_SMJ2_E.svg/1200px-Cones_SMJ2_E.svg.pngCones SMJ2 E.svg
"Cones SMJ2 E" by Vanessaezekowitz at en.wikipedia / Later version uploaded by BenRG. - Based on Dicklyon's PNG version, itself based on data from Stockman, MacLeod & Johnson (1993) Journal of the Optical Society of America A, 10, 2491-2521d http://psy.ucsd.edu/~dmacleod/publications/61StockmanMacLeodJohnson1993.pdf (log E human cone response, via http://www.cvrl.org/database/text/cones/smj2.htm) Transferred from en.wikipedia to Commons by User:Richard001 using CommonsHelper.. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

Cones SMJ2 E.svg http://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Cones_SMJ2_E.svg/1200px-Cones_SMJ2_E.svg.png
"Cones SMJ2 E" by Vanessaezekowitz at en.wikipedia / Later version uploaded by BenRG. - Based on Dicklyon's PNG version, itself based on data from Stockman, MacLeod & Johnson (1993) Journal of the Optical Society of America A, 10, 2491-2521d http://psy.ucsd.edu/~dmacleod/publications/61StockmanMacLeodJohnson1993.pdf (log E human cone response, via http://www.cvrl.org/database/text/cones/smj2.htm) Transferred from en.wikipedia to Commons by User:Richard001 using CommonsHelper.. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

Cones SMJ2 E.svg
"Cones SMJ2 E" by Vanessaezekowitz at en.wikipedia / Later version uploaded by BenRG. - Based on Dicklyon's PNG version, itself based on data from Stockman, MacLeod & Johnson (1993) Journal of the Optical Society of America A, 10, 2491-2521d http://psy.ucsd.edu/~dmacleod/publications/61StockmanMacLeodJohnson1993.pdf (log E human cone response, via http://www.cvrl.org/database/text/cones/smj2.htm) Transferred from en.wikipedia to Commons by User:Richard001 using CommonsHelper.. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

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Cornelius
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First, the electronics: Let's not confuse the type of power of a light emitting device with the type of light it produces.
Let's not confuse the type of power of a light emitting device with the type of light it produces. Everything that is mains powered is powered from AC. But this power first enters the power supply block, which converts it to DC. Failure of this power supply to output clean DC voltage will result in malfunctioning of the device, behaving as it is not powered at all, because semiconductors do not work when powered from AC. So, excepting classic incandescent light bulbs, no other light producing electronic devices use AC as power source.

This question is not about AC or DC current. It is about flicker frequency, light wavelength and their biological effects.

First, the electronics: Let's not confuse the type of power of a light emitting device with the type of light it produces. Everything that is mains powered is powered from AC. But this power first enters the power supply block, which converts it to DC. Failure of this power supply to output clean DC voltage will result in malfunctioning of the device, behaving as it is not powered at all, because semiconductors do not work when powered from AC. So, excepting classic incandescent light bulbs, no other light producing electronic devices use AC as power source.

This question is not about AC or DC current. It is about flicker frequency, light wavelength and their biological effects.

Let's not confuse the type of power of a light emitting device with the type of light it produces.
This question is not about AC or DC current. It is about flicker frequency, light wavelength and their biological effects.

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Cornelius
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