Chapter 6.2 The senses THE EYE

Human vision: depends on both the eyes and the brain Human vision: depends on both the eyes and the brain. The eyes sense light and form images. The brain interprets the images.

Seeing in 3-D and Color Humans and other primates see in 3-D since their eyes face the same direction and are only a few inches apart Both eyes focus on the same object but from slightly different angles. This allows the brain to determine the distance to the object. Special cells allow primates to see in color because they can tell the difference between wavelengths of light.

How does the eye work? Light passes through the cornea Pupil (opening in eye) looks black. This is surrounded by the iris (colored part) Lens (clear curved structure like a magnifying glass) To the back of the eye-Retina. This is made of cells called rods (dim light) and cones (color) The image is then sent through a nerve-Optic Nerve to the brain

Vision Problems Myopia-nearsightedness distant object blurry but close are focus Correct: concave lenses Hyperopia-farsightedness. can see distant object clearly but not close. Correct: convex lenses Astigmatism: Blurry vision far and near

Prep for eye dissection http://www. exploratorium Prep for eye dissection http://www.exploratorium.edu/learning_studio/cow_eye/ http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=cvp&wcsuffix=4153 (only works in firefox)