Vistar Insights

Light Still Activates Brain in the Brain of Blind Individuals

Tuesday, June 02, 2015

Why do people need to sleep in darkness? The light stimulates the brain, essentially keeping it awake.

A recent study conducted by researchers at the Univesrity of Montreal and Boston’s Brigham and Women’s Hospital found that light will enhance brain activity during cognitive tasks, even in those that are completely blind. Senior co-author of the study Steven Lockley indicated, “We were stunned to discover that the brain still respond significantly to light in these rare three completely blind patients despite having absolutely no conscious vision at all. Light doesn't just allow us to see, it tells the brain whether it's night or day which in turn ensures that our physiology, metabolism and behavior are synchronized with environmental time".

It was discovered that the study participants, all blind, had a non-conscious awareness of the light. Brains can “see”, or rather, detect light through a novel photoreceptor in the ganglion cell layer of the retina. These are separate from the rods and cones we use to see.

Light is a factor in determining the circadian rhythms that signal to the body when it should sleep or be awake. Our sleep patterns are regulated by light and darkness. Strong daylight is the most powerful factor in regulating our biological clock. Just becomes someone is blind does not mean they do not experience this.

For more information and resources for those who are visually impaired in Roanoke, Virginia, visit