We often notice that children rub their eyes when they feel sleepy, and adults also do this frequently when working with concentration for long hours. According to the Cleveland Clinic, adults may need to blink their eyes approximately 14 to 17 times per minute in order to spread tear secretions to the surface of the eye, keeping it moist and comfortable.
Rubbing the eyes may increase the chance of infection, especially if one has allergies due to exposure to dust, pollen, or pet dander. Use blue light filtering glasses when one needs to work on tablets for long periods to relieve eye strain.