What's Behind Your Eyes

The Science of Sight

- By Rani lyer

Our eyes act like a camera. They capture images from the world around us. The images can be individual objects or the features of the setting we are located in. Our eyes also help us to identify the vivid color of an object-a rose or an apple, for instance—from the surrounding background. Looking at the rose, we can guess how far it is from us. Our eyes can also discern the texture and other features of the flower. We do all this automatically, without thinking about it.

More Than a Camera

But a neuroscientist will explain that a human eye is more than a camera. It not only captures images but also transmits and interprets these images. An eye is a complicated organ with a deceptively simple structure. Some organisms possess light-sensitive cells clustered together, known as “simple eyes.” Such eyes can distinguish light and dark, but they can't detect objects or images. Even simple eyes, however, require an extremely complex mechanism to support vision.

Behind the Scenes

The process of vision begins when photons are first sensed by a specialized molecule in the eyes called 11-cis-retinal. Just as ice changes when exposed to heat, the molecule that chat captures the photon also changes ss shape and structure. This new molecule is called a rhodopsin. The energy of the photon continues to change the shape and structure of the rhodopsin into a new molecule. The new shape and structure is called metarhodopsin II. This shape is a perfect fit, like a piece in a jigsaw puzzle, for a gap in a giant protein.