Blind football, also known as futsal, is an adaptation of football for athletes with visual impairments including blindness. The sport, governed by the International Blind Sports Federation (IBSA), is played with modified FIFA rules, including that there is no offside. The field of play is smaller, and is surrounded by boards.
Teams are reduced to five players, including the goalkeeper, and may also use one guide, who is positioned off the field of play, to assist in directing players. The ball is equipped with a noise-making device to allow players to locate it by sound. Matches consist of two 25-minute halves, with a ten-minute break at half-time.
Football 5-a-side players are assigned to one of three sport classes based on their level of visual impairment:
- B1 - Totally or almost totally blind; from no light perception up to light perception but inability to recognise the shape of a hand.
- B2 - Partially sighted; able to recognise the shape of a hand up to a visual acuity of 2/60 or a visual field of less than 5 degrees.
- B3 - Partially sighted; visual acuity from 2/60 to 6/60 or visual field from 5 to 20 degrees
Teams are permitted to use sighted athletes as goalkeepers and guides; sighted goalkeepers cannot have been registered with FIFA for at least five years.
Two types of competition exist. For Class B1 games, only athletes with sport class B1 are permitted as players, with the exception of the goalkeepers and the guides, who may be class B2, B3, or sighted. For Class B2/B3 games, teams can field players in sport classes B2 and B3; at least two B2 players must be on the field at all times.