What are the black bars beneath American Footballer's eyes are used for? - Sports Stack Exchange

I often see football players with black bars right under their eyes. I can't figure out a reason why they are necessary. What are they used for?

Why is American football the only sport that requires eye paint to reduce glare? : r/answers

Here's Why American Football And Baseball Players Often Have A Black Stripe Drawn Under The Eyes - I'm A Useless Info Junkie

Virginia RB Perris Jones undergoes spine surgery in Louisville after injury in game

Do professional footballers have their own personalised boots? - Quora

Warren Sapp - Wikipedia

Jerry Falwell, Jr.: Sin and Scandal at Liberty University

Who is the greatest American football player from the NFL or earlier leagues that most people, even big fans of the sport, don't know much about? - Quora

Football player dominant region determined by a novel model based on instantaneous kinematics variables

How effective are the black bars football players put under their eyes? : r/askscience

Flawless Fit For The Foot

Killing Floor (Jack Reacher): Child, Lee: 9780425264355: : Books

Wife Leaves Footballer Caught On Video Performing Lewd Act On Teammate

Christophe Galtier: The man chosen to replace Mauricio Pochettino signals change in Paris Saint-Germain approach, Football News

The Business of Barcelona

A public data set of spatio-temporal match events in soccer competitions