Quote:
Originally Posted by Krystian Galaj
Quite so. So, what does the fact that:
a) my eyes hurt when the only light source is a screen of iPhone, set to minimal brightness, in complete darkness, and
b) they don't hurt when I read on e-Ink, in full sunlight or under bright light of the lamp
tell you about relevance of the symptoms I described to light sensitivity?
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The eye adjusts to the total amount of light. The field of vision is a little different from person to person, but I'm guessing that your hand held device occupies less than 10% of it (this will largely depend on how close it is to your eyes). A computer screen will do more or less the same, since even though it is bigger, it is further away. So if you are reading in a dark room, your eyes will adjust mostly to the environment, trying to get as much light as possible. Beside the size of the FOV, there is also the matter of receptor density, which can also differ from person to person, making it possible for some eyes to adjust more to the light going to the center of the FOV.
For the pain and headache, it isn't necessary that all the receptor cells in your eyes feel the same large number of photons, a small area on your fovea (the part of the retina where the image of letters will be formed) is enough. And at the center of the fovea there are around 150,000 receptors /mm^2.
The fact is that you are not going to read you E-Ink in a completely dark room, and the amount of light that is scattered of the capsules of ink will never rival the light emitted by the LCD in terms of photons/mm^2 on your retina.