Scientists in Spain have confirmed what football fans around the world have always suspected -- that referees and their assistants have flawed eyesight.
In an article published in the medical journal, The Lancet, they say that because of the way the eye focuses, a time-delay occurs as the most sensitive part of the retina tries to pick up images.
This means officials may see two players as being several metres apart when, in fact, they are level at the time their position is gauged.
The delay is especially relevant to the offside rule, where a player is deemed to be offside if two opposing players are between him and the goal-line at the time the ball is played.
A BBC sports correspondent says the findings suggest football fans should be more understanding of referees -- unless of course their team is losing.
From the newsroom of the BBC World Service