 B3 traces its history to the early history of blind sport . There was a belief that those with vision impairment that was less severe had a competitive advantage over competitors who had more severe impairment . Classification was developed by the IBSA to insure more even competition across the different bands of visual acuity . In 1976 , the International Sports Organization for the Disabled ( ISOD ) developed a blind classification system . Parallel to this , IBSA and national blind sport associations were developing their own classification system , with the IBSA one based on visual acuity in place by 1980 . The rise of the IBSA classification system for blind sport meant the ISOD classification system failed to gain traction in blind sports competition . 
