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The eye uses many layers of nerve cells to convert light into sight

Wei Li, National Eye Institute, National Institutes of Health

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The eye uses many layers of nerve cells to convert light into sight 

This image captures the many layers of nerve cells in the retina. The top layer (green) is made up of cells called photoreceptors that convert light into electrical signals to relay to the brain. The two best-known types of photoreceptor cells are rod- and cone-shaped. Rods help us see under low-light conditions but can't help us distinguish colors. Cones don't function well in the dark but allow us to see vibrant colors in daylight.

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This page last reviewed on August 30, 2017