Looking at your phone or any other screen, be it tv,
computer, table has no effect on your vision, what is important here is the bightness of the light should be within
the normal angles, the problem will be, if the ratio of the brightness and
contrast is normal, if otherwise then there will be no any problem.
Your eye will
only have problem when the screen is very bright or vey deem, your pupil become
larger to allow more light enter your eye, this will tire out your eye ,
likewise when the light is very bright the pupil become smaller so that only
smaller amount of light will enter your eye,
You wont have
any problem when the amount of light remain constant, because your pupil will only be smaller or larger at
a time but the problem starts only when brightness of the light is constantly
changing, this will continuously move the eye pupil back and forth and thereby
wearing –out your eye , this will eventually cause eyestrain.
Secondly your eye will only have problem if you are
using only one eye while the other is
close, this happens when a pillow or blanket is over the eye, when this happen
a problem called photo-bleaching result, this is the wearing-out of one eye to
the other, one eye is adapting to the bright light while the other is adapting
to the dark , the best solution is to use both of the eyes equally.
