5 ms·

Is that really supported by empirical trials? A short search online seems to point to that being somewhat disputed. I'm all for contradictory evidence though if

by olodus 6y ago

Is that really supported by empirical trials? A short search online seems to point to that being somewhat disputed. I'm all for contradictory evidence though if you have some I missed. Yeah sure a screen is emitting light which maybe makes it worse for the eyes to look at in some ways and situations than a paper page, but "looking at light" is almost an oxymoron - isn't that what eyes do?

groby_b 6y ago
Eyes usually look at diffusely reflected light, which has a different impact than direct light. A white reflective surface (whiteboard) in direct sunlight is 1.6cd/cm^2. Consumer monitors are ~300cd/cm^2 (I'm not sure how much bearing this actually has on eye health, this is just to illustrate how looking at a monitor and at a piece of paper is significantly different)
- TremendousJudge 6y ago
  >A white reflective surface (whiteboard) in direct sunlight is 1.6cd/cm^2. Consumer monitors are ~300cd/cm^2 Why does it hurt my eyes to look outside after a while looking at a screen in a well lit room? (the sun is not directly visible, just buildings, trees and sky)
  - atomicnumber3 6y ago
    Because the sun is an enormous sphere of hydrogen-helium plasma with a core that's undergoing fusion just due to gravity. Even indirect sunlight is still a very large amount of light and energy. I don't mean to sound flippant, but I think sometimes people forget just how insanely energetic stars of all sizes are.
    - TremendousJudge 6y ago
      But GP's point was that a screen is much brighter than a sunlit surface. You can't both be right, or I'm missing something.
- yoz-y 6y ago
  Hm, to be honest I find reading a book is direct sunlight quite more challenging than staring at a screen, because the reflected light is quite unbearable.
- lukevp 6y ago
  Your units are wrong. Monitor brightness is measured in square meters not square centimeters. A square centimeter is 10,000 times smaller than a square meter.
- Cerium 6y ago
  I think there is a unit error here. I believe that sunlight on white paper is about 1.6cd/cm^2, while consumer monitors are about 300cd/m^2 (meter not cm). Essentially, you want the brightness to match the environment. http://www.infocomm.org/filestore/display_specs_and_human_vision_1_v3.pdf http://www.infocomm.org/filestore/display_specs_and_human_vi...
  - groby_b 6y ago
    There is indeed. Oops. I'd delete - no point polluting the Internet with more bad info - but time window has expired. Thank you for the correction!
- beervirus 6y ago
  As noted, your units are wrong. A white reflective surface in sunlight is FAR brighter than a computer monitor.
- gowld 6y ago
  cd/m^2, not cd/cm^2 I don't understand. Monitors are intended to be set to the same brightness as the ambient environment. 300cd/cm^2 is max, not average. Of course shining a monitor in your face at maximum brightness is bad, just like staring at a light bulb all day is bad.
- greenshackle2 6y ago
  You've got your units wrong. Very obviously so, to anyone who has ever taken a laptop outside in daytime.

by olodus 6y ago

groby_b 6y ago

Eyes usually look at diffusely reflected light, which has a different impact than direct light. A white reflective surface (whiteboard) in direct sunlight is 1.6cd/cm^2. Consumer monitors are ~300cd/cm^2 (I'm not sure how much bearing this actually has on eye health, this is just to illustrate how looking at a monitor and at a piece of paper is significantly different)

TremendousJudge 6y ago
>A white reflective surface (whiteboard) in direct sunlight is 1.6cd/cm^2. Consumer monitors are ~300cd/cm^2 Why does it hurt my eyes to look outside after a while looking at a screen in a well lit room? (the sun is not directly visible, just buildings, trees and sky)
- atomicnumber3 6y ago
  Because the sun is an enormous sphere of hydrogen-helium plasma with a core that's undergoing fusion just due to gravity. Even indirect sunlight is still a very large amount of light and energy. I don't mean to sound flippant, but I think sometimes people forget just how insanely energetic stars of all sizes are.
  - TremendousJudge 6y ago
    But GP's point was that a screen is much brighter than a sunlit surface. You can't both be right, or I'm missing something.
yoz-y 6y ago
Hm, to be honest I find reading a book is direct sunlight quite more challenging than staring at a screen, because the reflected light is quite unbearable.
lukevp 6y ago
Your units are wrong. Monitor brightness is measured in square meters not square centimeters. A square centimeter is 10,000 times smaller than a square meter.
Cerium 6y ago
I think there is a unit error here. I believe that sunlight on white paper is about 1.6cd/cm^2, while consumer monitors are about 300cd/m^2 (meter not cm). Essentially, you want the brightness to match the environment. http://www.infocomm.org/filestore/display_specs_and_human_vision_1_v3.pdf http://www.infocomm.org/filestore/display_specs_and_human_vi...
- groby_b 6y ago
  There is indeed. Oops. I'd delete - no point polluting the Internet with more bad info - but time window has expired. Thank you for the correction!
beervirus 6y ago
As noted, your units are wrong. A white reflective surface in sunlight is FAR brighter than a computer monitor.
gowld 6y ago
cd/m^2, not cd/cm^2 I don't understand. Monitors are intended to be set to the same brightness as the ambient environment. 300cd/cm^2 is max, not average. Of course shining a monitor in your face at maximum brightness is bad, just like staring at a light bulb all day is bad.
greenshackle2 6y ago
You've got your units wrong. Very obviously so, to anyone who has ever taken a laptop outside in daytime.