How Do We See?

The eyes work like an amazing camera that captures millions of images and records it in our memory(brain).


When light hits an object, the object absorbs some of the light and reflects the rest of it. The wavelengths reflected or absorb┬ádepends on the properties of the object.The wavelengths of reflected light determine what color we see. The light wave reflected from the object enter the eyes, and pass through the iris and pupil to reach the lens. The lens focuses the rays on the retina to form an image. The retina turns the light rays into signals that our brain can understand. The retina uses light-sensitive┬ácells called rods and cones to see. Cones are one type of photoreceptor, the tiny cells in the retina that respond to light.┬áMost of us have 6 to 7 million cones, and almost all of them are concentrated on a 0.3-millimeter spot on the retina called the fovea centralis. The rods help us to see it’s dark. The cones help us to see the color. There are three different types of cones to help us to see different color: red, green and blue. 64 percent of cones respond most strongly to red light, while about a third are set off the most by green light. Another 2 percent respond strongest to blue light. The rods and cones of the retina change light into electrical signals for our brain. The optic nerve takes these signals to the brain. Actually, the image at the retina is upside down from the actual image.



Author: Wan


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