589640 A method of detecting a microsleep event in a person (10) is disclosed. It is particularly useful for drivers of vehicles. The method includes determining a number of eye openness factors by measuring a number of distances between an upper eyelid and a lower eyelid of at least one eye over a time period using a camera (102) and processor (106). Graphical representations of the eye openness factors are then generated. Changes in the eye openness factors over the time period are correlated with a reference eye closure pattern indicative of the microsleep event. If such an event is determined to have occurred an alert make the person aware. Also disclosed is a microsleep event detection device (100).
