Can the human eye detect an offside position during a football match?

Two errors occurred in this article by Francisco Belda Maruenda in our Christmas issue (BMJ 2004;329:1470-2, 18-25 Dec). In the section headed “Is the human eye able to detect an offside offence?” the final sentence of the first paragraph incorrectly states: “The time that the eye needs to detect all the objects is the sum of the eye movements and the accommodation that it has to do.” In fact, the time needed is the sum of the integration of the eye movement and accommodation.

The caption for the bottom half of figure 2 (p 1471) should have stated that this showed an incorrect call of offside (not a correct call)—the assistant referee is holding up a flag for an offside that does not exist.