Football visors have not been around for long. They first appeared in competitive football in the 1980s as a way to protect the injured eyes of active football players. But the use of these protective visors have exploded since then, and many players choose to wear them out of personal preference. Even so, the preventative benefits of visors are indisputable.
The primary function of visors is protective in nature. Some players wear visors temporarily to prevent damage from occurring to an existing injury, and then remove the visor once the injury has healed. But other players choose to wear visors permanently to prevent an injury from occurring -- this can happen if fingers or a foot strike the eyes in the helmet's opening.
Another key benefit to visors is their ability to improve a player's vision. This is most notable when the ball becomes lost in the sun or overhead lights -- visors can operate as sunglasses and improve vision when staring into bright lights. According to ESPN.com's Page 2, some also increase color contrast, making vision sharper on the field.
According to ESPN.com's Page 2, some players choose to wear certain visors as a means of expressing themselves. The visors can feature colors and patterns that are visible from the exterior and set a player apart from the rest of the uniformed players. In 2005, for example, Miami Dolphins running back Ronnie Brown chose to wear a sunburst-patterned visor in a game. However, he was issued a fine from the league for violating uniform code.
Although most football leagues allow visors to be worn, some teams do not allow the visors to be worn unless the player has a medical need for one. This is up to the coach's or team's preference. In addition, many leagues, including the NFL, have rules on what type of visor may be worn. The NFL requires each visor worn in a game to be approved by the NFL before its use. If this rule is violated, the offending player is reprimanded with a fine.