Would It Be Possible To Have Three Eyes?

Would it be possible to give someone a third eye, in addition to their two normal eyes, somewhere on their body? Could our minds handle more than two eyes? Having three eyes would be really cool.

Many creatures (insects) sport more than two eyes so it is possible. However I don’t think our visual cortex could integrate a third eye’s input without some serious re-wiring.

I believe the brain is rather more flexible than many people assume: I remember reading about an experiment where someone wore glasses that constantly made things look upside-down; after a few days, internal brain functions rearranged themselves and suddenly everything looked normal. Then the glasses were removed. And the readjustment took the same amount of time.

That’s a lot simpler than adding another eye though. Assuming that it would be possible to find a place to connect all the eye nerves, I don’t see why the brain dould not adjust to the new input in time. But it might screw up the processing from the two existing eyes bigtime until everything adjusted.

But that’s a HUGE assumption, and I’m not sure it’s even doable. The eye is basically part of the brain, is it not? Aren’t there paired structures all through the brain that connect to it? You might almost have to add another third to the brain…

I vaguely remember reading about work to allow skin twitches to control a third (mechanical) arm though.

I have just two words for you:

“Pineal gland.”

Pineal gland? Explicame, por favor.

…all of this, of course, is moot, as there’s no way to graft nerve tissue together. Not yet, at least.

The pineal gland had a retinal like structure histologically. It is responsible for the production of melatonin and has been postulated to have represented a third eye, although I believe that has been pretty thoroughly debunked.

I’m surprised that the pineal gland - eye connection is considered debunked. Isn’t the pineal gland of the tuatara still light-sensitive?

The pineal gland is sometimes referred to by pyschics, mystics, and others of such ilk as the “third eye”, and is felt by them to have some extraordinary significance in communicating with higher planes and so on. Here’s a sample of the general cant:


Actually, the gland secretes melatonin, and seems to have something to do with regulating the sleep cycle, circadian rythm and other biological clock functions. The gland is stimulated by nerves from the eyes. In some animals, the gland is near the skin and can receive light directly rather than receiving input from the eyes. In some, such as the tuatara lizard, an actual “third eye” is present.

A couple other people got in while I was typing. I should add that the mechanism in animals like the tuatara, and the general structure of the organ serve as heavy contributory factors to the mystic beliefs in the power of the organ, of course.

The Groaci would point out that we are lowly creatures unaware of the subtelties of trinocular, quadrocular and other higher orders of vision, of course …

What I meant was that really no one believes it was ever used for sight. In humans, it is buried deep in the brain but does receive information from the eyes and those parts of the brain related to interpretation of visual information.

So, if we lived in a Euclidean four-dimensional space, would we require three eyes to see in three dimensions and infer the fourth dimension, just as we use two eyes now to infer the third?

No- two eyes would suffice, no matter what the number of dimensions.

Hey- here we all are, discussing four-dimensional beings with three eyes! And I haven’t even had breakfast yet!

A thid eye would offer an advantage in that it would let us judge vertical movements as accurately as horizontal ones.

Is it possible to have one eye only…cyclops-like…that works? Has that ever happened?

What about the armour deisgn?
The eyeball sits in the eye socket, to keep most of its delicate structure encased in bone
So unless you want to evacuate another large hole in your head or somewhere else in your body and line it with bone, then a third eye would be very easily squashed and so, non-viable.

Another eye socket wouldn’t be necessary if you went for a solid-state approach. A photocell array hooked up to the visual cortex via small electrodes which pass through the skull would likely give some sort of additional light sensitivity. The device could be armored with a quartz cabachon that also acts as a lens to focus incoming photons.

Well, lots of people get by with one eye. You lose depth perception but it does appear to be a major handicap. Isn’t the eye considered part of the brain and not as a seperate organ physiologically since its so integrated?

Right. The point is that there’s an incredible amount of image-processing that goes on, starting with the nerve cells in the retina, which do contrast enhancement, simple color processing, movement detection and simple shape recognition. The optic nerves from each eye cross over, exchanging information from each eye to form a left and right visual field (each of which includes information from both eyes). The visual cortex continues image-processing, integrating context and content information from other parts of the brain to do higher-level image-processing and eventually identify items and pass this information to a whole range of other brain areas.
Integrating a third eye into this scheme is a challenge far, far, far bigger than just learning how to culture nerve cells and encourage them to make connections.
Not saying it’s impossible in theory, but adding a third hand would be at an order of magnitude easier.

What about a failed siamese twin set, as in this case … since she has extra internal organs and limbs, would a third eye be possible under these sad (poor medical care, nutrition, etc) conditions?