Phosphorescent symbols on the screen hold a hypnotic attraction. So intensely do they attract that human eyes blink less frequently when viewing computer screens. The cornea of the eye requires frequent fluid baths, and eyelids normally bathe and massage the eyeballs by blinking every five seconds. Interacting with a computer calls for concentration, and the sustained stress tends to fix vision in a stare. As blinking decreases, the eye muscles have difficulty focusing.
Users also tend to hold their breath when trying to see the screen better.
This decreases blood circulation and increases bodily tension. The resulting strain eventually leads to refractive error, most often chronic myopia. Lenses are symbols of modern civilization. The human eye evolved naturally to focus on distant objects. Looking into the distance, the internal eye muscles relax.