French philosopher René Descartes (1596-1650) emphasized the pineal gland in his writings, calling it the seat of the soul and “The part of the body in which the soul directly exercises its functions.” He contended that this was centre at which the soul and body interacted, and where we receive our messages from the Divine. Even Jesus says in Matthew 6-22: “The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.”, so the idea of there being a spiritual eye is no new idea.
This is not proof that the pineal gland is a spiritual eye seeing into other dimensions, but it is proof that it has the biological potential to be an actual eye. So now we have a solid scientific evidence to establish that the pineal gland is in fact a third eye, and we can now begin to speculate why it evolved and if it serves any purpose of spiritual significance.
For example, a lot of people who have had out-of-body experiences report a silver cord linking their astral body back to their physical body located either in between the eyes or at the back of the head where the pineal gland would be. Could it be that our astral body, which exists in our physical body yet has access to higher dimensions, receives literal information from psychic and spiritual realms in the form of photons and images, which then get fired down the silver cord into the visual cortex of the brain where they get processed by the rods and cones in the pineal gland? Is the pineal gland a little television for worlds unseen to the biological eye? With the scientific proof that this gland can function like an eye, we now have these avenues open for speculation.
Unfortunately, the pineal gland can become calcified from heavy metals and fluoride which can restrict its biological function as a producer of melatonin (which regulates sleep cycles) and may also inhibit and psychic or spiritual function it may have.