Why shouldn't we use phone in dark? ?

Well, it might be bad for the eyes. But more studies need to be done

That has to do with HEV light, known as blue light. This light is the visible portion of the light spectrum that has the shortest wavelengths - which might be why it can cause damage to living tissue, in this case, the eyes.

A damage can happen in the tissue in the retina of the eye that is consistent with retinal changes associated with macular degeneration; leading cause to permanent vision loss in the elderly.

Another problem might be the fact that blue light is daylight - as the sun emits it as well - and it can cause problems with your sleeping cycle, but that’s another issue.

Because she’s in school