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How the Eye Works

Our eye works like a camera. For us to get a clear image, light must be in focus. Just like a camera, we have a lens in our eye that will adjust to give us clear vision at different distances. The retina at the back of the eye works like the film of a camera. It absorbs light and sends the image to our brain.


Light first goes through the cornea, which is the clear dome of tissue on the front of our eye. The light then travels through the black circle in the center of our eye, known as the pupil. The pupil is actually an opening in the center of the iris (the colored part of our eye). Our iris is what allows our eye to control the amount of light entering the back of the eye. When it’s dark out our eyes need all the light they can get in order to see clearly so the iris makes our pupils larger. The opposite happens when it’s bright outside. Because we don’t need as much light, the iris makes the pupils smaller.


After light goes through the pupil, it travels through the crystalline lens. As mentioned above, the lens changes shape to focus light onto our retina. The retina is a multilayered thin tissue inside the eye which absorbs light. There are millions of individual cells in the retina called rods and cones, which convert light into an electrical signal. These signals are sent via fibers that come together at the back of the eye to form the optic nerve. This nerve works like a cable by connecting the eye to the brain, and allowing images to be sent along it.

Written by: Dr. Giannonatti, optometrist since 2019

eye diagram
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