Eye : VisionThe eye is a complex organ made of several parts. The ability to see is dependent on these parts working together. We use our eyes in almost every activity we perform. The eyes allow us to see shapes, colors, and dimensions of objects by processing the light they reflect. Our eyes are able to see in bright or dim light, but they cannot see objects when light is not present. The following image is a guide to the many parts of the human eye and how they function.
Source : http://vision.about.com/od/commonvisionproblems/ig/Image-Gallery--Eye-Anatomy/index_t.htm
Anatomy of the eye External and internal eye anatomy
Lateral eye anatomy Eye lens anatomy