Answer:
helooooooooooo I am not in any army but also hiii
Digital devices, smartphones included, emit what we call the blue light. It has a wavelength between 380 to 470 nm. This is the only light that can penetrate the retina of the eyes. Hence, prolonged exposure to blue light, especially during at night, will cause damage to the retina resulting to sleep disorders or worst, cataracts.
I believe if I remember correctly, he/she is watching soldiers cross a waterway or bridge.
