The fundamental mechanism seems to be that light mode causes pupils to contract by exposing the eye to more light. This decreases spherical aberration and increases depth of field just as using as smaller aperture on a camera lens does.
Staring into a light source that contrasts enough with the ambient light to contract my pupils is uncomfortable. I don't want to do that even if it makes me read faster.
Comments
The fundamental mechanism seems to be that light mode causes pupils to contract by exposing the eye to more light. This decreases spherical aberration and increases depth of field just as using as smaller aperture on a camera lens does.
Staring into a light source that contrasts enough with the ambient light to contract my pupils is uncomfortable. I don't want to do that even if it makes me read faster.