The pineal gland – “the third eye” – has gained a mystical significance in spiritual circles. Many believe it is important – few understand what it does.
It weighs about 150 mg and sits in the depression between the superior colliculi at the back of the corpus callosum. The pineal gland is actually not a part of the brain, although it is connected to it .
The jury is still out on that one, but we do know that a calcified pineal gland leads to a defective sense of direction . It has also been implicated in schizophrenia . Increased intake of fluoride might be a significant cause of calcified pineal glands , so avoid ingesting large amounts of fluoride.
The pineal gland creates the pineal hormone, called melatonin, out of another spiritually important chemical, serotonin.
The melatonin production and activity in the pineal gland is reduced in response to daylight or artificial bright light. Darkness, on the other hand, activates the pineal gland and stimulates production of melatonin.
Melatonin has strong sedative  effects and is vital in sleeping. An unhealthy pineal gland will result in unhealthy sleep patterns. Melatonin has also been shown to have hypnotic effects [7,8]. If you want to activate your third eye, you need darkness.