There is an organ in your brain, attached to the third ventricle, which is often referred to as the third eye. The ancient Greeks believed this pinecone-shaped gland to be our mystic connection to the “Realms of Thought”. Descartes referred to it as the “Seat of the Soul”. This gland lies above and behind the pituitary gland. Have you guessed what organ I am hinting at?

It is the pineal gland.

The pineal gland is part of the endocrine system; it synthesizes and secretes melatonin, a hormone that affects the biorhythms and reproductive function of many animals.

A high level of melatonin makes you sleepy and less fertile. The duration of melatonin secretion each day is directly proportional to the length of the night, as melatonin is only secreted in detectable levels during the hours of darkness. As the pineal is sensitive to the levels of the light, this ability has led some to nickname the pineal the "third eye".

The pineal gland works closely with the hypothalamus and the pituitary gland. Melatonin receptors are found mainly in the hypothalamus. When there are high levels of the melatonin hormone, the hypothalamus inhibits pituitary gland from producing gonadotrophic hormones. These hormones affect the sex drive and fertility of most animals. So, when it is winter and the nights are longer, you tend to find animals that can hibernate, will hibernate, and most animals will not be mating. Even if the animals are sexually active, they will be less fertile, as the gonadotrophic hormones stimulate the activity of the gonads - the ovaries, the testes.

The Reptile with the Third Eye

The tuatara of New Zealand has a well developed pineal gland. The tuatara is not a lizard, but a last remnant of a group of reptiles that evolved along side the dinosaurs. This creature has primitive bone structure, and only starts breeding after it is twenty years old. The eggs take around four years to develop inside the mother tuatara, and then take a further year to hatch. Because they are slow breeding, they have become extinct on the New Zealand mainland, due to predation and loss of habitat

The tuatara's best known feature is its pineal “Eye”. Externally, it looks like a tiny spot on top of the animal's head, the only visible pineal gland known in nature. The actual “eye” is a clump of the light-sensitive cells situated at the top of the animal’s brain, just below a small hole in the skull. This third “eye” probably helps regulate the tuatara's exposure to the sun and so regulate its body temperature.

The New “Third” Eye

With thanks to my husband, Brian Green, for letting me use the data
from his uni assignment.

The virtual retinal display (VRD) is the latest development in head mounted displays. These are designed to overcome the limitations of the head mounted displays (HMD), such as cost, wearability and the quality of the rendered image.

Virtual retinal displays are a major advancement of the scanning laser ophthalmoscope technology, scanning modulated laser light directly onto the viewer’s retina to create a flicker free high-resolution image. Virtual retinal displays have a number of technological advantages of current display technology. They provide:

The development of this scanning technology for rendering images was a fortuitous observation by R. H. Webb. Webb noticed that when the optical beam was modulated by a source, for example: a video, the users were able to see the rendered image. At this time the image were of low-quality and suffered greatly from flickering. However, when the source was rendered using a properly modulated signal, this created a detailed, high-quality, full-colour image, and eliminated the flickering.

One advantage of this software is that it can take the standard video output from the computer and generate pseudo three-dimensional images to the user. This three-dimensional imaging would allow user to sense depth with in the image, which would be of great benefit to the visually impaired.