If you’re like me and don’t know much about American football or baseball, you may find yourself wondering why these football or baseball players are sometimes shown wearing war-paint-like black lines under their eyes. Is it done to intimidate the opposition or is there another reason for this decoration?
The name for this black grease that is applied under the eyes is “eye black”, and it’s often made with beeswax that has been blackened with carbon. Why is it blackened? Because this is the best colour to absorb light. Why would it need to absorb light? To stop glare entering the players eyes.
If sunlight or stadium lights are shining, there’s a chance that the light will reflect off their cheeks, and into their eyes, and this may impair the player’s sight and therefore their game. A study by DeBroff & Phak (2003) has shown that absorption of this light by the black paint on their cheeks reduces the glare and improves contrast sensitivity.
DeBroff & Pahk 2003. The Ability of Periorbitally Applied Antiglare Products to Improve Contrast Sensitivity in Conditions of Sunlight Exposure. Archives of Ophthalmology 121 (7): 997–1001.