Blink rate

The number of times the eye blinks per minute; normally around 15 in adults, dropping to 4 to 5 during focused screen use.

A normal resting blink rate is roughly 12 to 18 blinks per minute. During focused screen work — reading, gaming, coding, video editing — blink rate drops by 50 to 60 percent, sometimes lower for highly focused tasks. The result: the tear film evaporates between blinks, the cornea is exposed, and the eye develops the burning, gritty feeling characteristic of screen-related dry eye. The 20-20-20 rule's short break naturally resets blink rate; consciously blinking several times during the break amplifies the effect.