1. Tension headaches
Extremely high contrast from lit screens can cause headaches.
Reading dark print on an extremely bright background can lead to spasms of the muscles at the temples, which causes stress headaches, he said.
2. Dry eye
When looking at something in the distance, your eyes automatically blink a certain number of times.
However, blink rate slows down when you look at things that are closer to your face, which means tears evaporate more quickly than when you were blinking more frequently.
3. Eye strain
Spending hours on a computer or hand-held device keeps the eyes converged and strains the eye muscles to cause headaches. The eyes are generally more comfortable when they are parallel (your eyes are parallel when you look at far distances).