Kezako: can we really trust our eyes?

The human eye can differentiate nearly eight million shades of color. However, this very advanced organ gives little information to our cortex to create an image. So what exactly happens when we see? Unisciel and the University of Lille 1 explain to us, with the Kézako program, how this surprising organ works.

The operation ofeye is analogous to that of a camera or a camera. The light first cross the cornea who takes care, with the crystalline, focusing the image. The amount of light is then managed by the pupil, which opens and closes like a diaphragm. Finally, the image forms at the back of the eye, on the retina. It is she who will interpret the light with some sensors shaped cones and of sticks.

Each cone is sensitive to one of the three colors, yellow, blue or green. The sticks intervene when the light is very weak and only capture in black and white. Once received by these sensors, the image is sent to brain speak optic nerve to be further processed by the visual cortex. The information provided by theeye are sketchy and the actual image is only sharp and in color in the center. A large part of our peripheral vision is therefore only an interpretation of the brain.

© Unisciel© Christian G., FlickrCCby-nc-sa 2.0

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Kézako? is the series that answers the science questions that everyone is asking. In a short and relaxed format, lasting a few minutes, the series tackles questions of mathematics, physics, chemistry, computer science, life and earth sciences. Produced by Unisciel and Lille 1 University, carried out by Maxime Beaugeois and Daniel Hennequin, it addresses the principles and applications of science. You can find all the episodes on kezako.unisciel.com.