Where does this come from, and can I check it?

The brain compares slightly different images from each eye to judge distance. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a human body fact?

Yes. It sits on the Human Body shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Two forward-facing eyes create three-dimensional sight

The brain compares slightly different images from each eye to judge distance Human eyes sit about six centimetres apart, so each sees a scene from a marginally different angle. The cortex matches features between the two images and converts the disparity into depth, a process called stereopsis. It works best close up and contributes little beyond a few dozen metres. It sits in Mondo's human body collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Encyclopaedia Britannica

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Science trivia

More facts like this

Eye muscles are the most active muscles in the human bodySix delicate muscles move each eye over one hundred thousand times daily The cornea is one of the few body parts without blood vesselsTransparent eye tissue receives oxygen directly from tears and air The human retina contains over one hundred million light receptorsRods enable dark peripheral vision while cones register fine detail and colour Ciliary muscles alter lens shape instantaneously to focusSmooth muscle accommodation keeps objects clear across varying distances Each eye has a blind spot where nerves exitThe optic disc carries no photoreceptors, so a small patch of vision is blank Light in one eye makes both pupils shrinkSignals cross in the brainstem so each pupil responds to light entering either eye

Tags: vision, depth, eyes

Two forward-facing eyes create three-dimensional sight: the short answers

Where does this come from, and can I check it?: The brain compares slightly different images from each eye to judge distance. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a human body fact?: Yes. It sits on the Human Body shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.