Squint

[2][3] Pinhole glasses, which severely restrict the amount of light entering the cornea, have the same effect as squinting.

However, according to Robert MacLaren, a professor of ophthalmology at the University of Oxford, this is nothing more than an old wives' tale: the only damage that can be caused by squinting for long periods is a temporary headache due to prolonged contraction of the facial muscles.

Many eye expressions convey specific feelings, but squinting is more ambiguous, as it can signal multiple emotions, such as suspicion, toughness, and desire.

Clint Eastwood built his career out of mastering squinting, expressing everything from terse stoicism as the Man With No Name in The Good, the Bad and the Ugly to romantic desire as Robert Kincaid in The Bridges of Madison County.

Manohla Dargis once quipped that "eyes may be windows to the soul, but men like Eastwood like to keep the shades partly drawn.