http://www.livescience.com/humanbiol...squinting.html
Squinting at a computer screen reduces how often you blink and can lead to dry, irritated eyes, a new study finds.
We squint to focus our eyes for a better look.
But just a slight amount of squinting reduced blink rates by half, from 15 blinks a minute to 7.5 blinks a minute, the study revealed. The more that participants squinted, the less they blinked. The less they blinked, the more their eyes ached or burned and became dry.
More at the link.