Wikipedia
Eye-gouging is the act of pressing or tearing the eye using the fingers or instruments. Eye-gouging involves a very high risk of eye injury, such as eye loss or blindness.
Eye-gouging as a fighting style was once a popular form of sport fighting in the back-country United States, primarily in the eighteenth and nineteenth centuries.
Eye-gouging is prohibited in modern sports. It is a serious offence in rugby football codes where it occurs rarely. It is prohibited in combat sports, but some self-defense systems teach it. Training in eye-gouging can involve extensive grappling training to establish control, the eye-gouging itself being practiced with the opponent wearing eye protection such as swimming goggles. Yuki Nakai went on to win a bout in the Vale Tudo Japan 1995 tournament after his opponent performed an illegal gouge that blinded him in his right eye.
Eye-gouging is a serious offence in rugby union where a player uses hands or fingers to inflict pain in an opponent's eyes. The game's laws refer to it as "contact with eyes or the eye area of an opponent" but such incidents are usually referred to as " eye-gouging" among players and in the media.