London, March 14 : Wearing an eye mask can potentially enhance cognitive functions of the brain as it blocks ambient light while we sleep, suggests a study. Sleep is crucial for alertness and for preparing the human brain to encode new information. However, ambient light, like an outdoor street light shining through your window, can influence sleep structure and timing. The study, published in the journal Sleep, showed that wearing an eye mask blocks light during night sleep and improves memory and alertness. "Our findings suggest that wearing an eye mask during overnight sleep can improve episodic encoding and alertness the next day," wrote Viviana Greco, from School of Psychology at University of Cardiff, along with other researchers in the paper. The team conducted two experiments to understand how sleep masks help. In the first experiment, 94 people in the age group of 18-35 wore an eye mask while they slept every night for a week and underwent a control condition in which light was not blocked for another week. Five habituation nights were followed by a cognitive battery on the sixth and seventh day. This revealed superior episodic encoding and an improvement on alertness when using the mask, the researchers said. In the second experiment, 35 people of the same age group used a wearable device to monitor sleep with and without the mask. This replicated the encoding benefit and showed that it was predicted by time spent in slow-wave sleep. Furthermore, the benefit to memory was predicted by the time spent in slow-wave sleep while wearing the mask. This suggests wearing an eye mask during sleep is an effective, economical, and noninvasive behaviour that could benefit cognitive function and lead to measurable impacts on everyday life, the researchers said. /IANS