19-111 OUR AMAZING VISUAL SYSTEM (A REPEAT)
Robert Springer, Wednesdays 10 am - 12 noon
Sonoran Room, February 20, 27, March 6, 13, 20, 27
This course discusses the incredible human visual perception system. While the eye is often simply compared to a camera, in this course participants will learn that the visual system is, in fact, very different than that of a camera. Instead of a camera’s sharp lens, humans actually have two low-quality lenses. The images that enter the eye travel through a substantial number of blood vessels before getting to the eye's retina. Amazingly, the visual system erases these blood vessels from view. In addition, the retina has a hole in it that the visual system somehow fills in. The retinal film contains about 130 million receptors but contains only about 1 million nerves connecting those receptors to the brain. The class will discuss why there are so many receptors for each nerve and the fascinating image processing that results from this interconnection of many receptors to few nerves.
The human eye constantly shakes. The eye must shake or the image seen will disappear. Interestingly, images are not seen all at once. Participants will discuss how the visual system breaks down images into pieces and gathers information on edges, motion, direction, and color for each piece. Then attendees will see how the system puts all these pieces back together into the complete "picture" that is seen at any moment. The course will conclude with discussions of visual problems that occur as we age.