2. How We See Chapter 11 - 4

3. *Light enters the eye through an opening called the pupil. The light is refracted by the lens and cornea and creates an image (upside down) on the retina. The image is transferred to the optic nerve; which sends it to the brain. The brain turns the image right side up and interprets it for you. The iris controls the size of the pupil to make sure it lets in just the right amount of light. Vision Path Investigating Human Biology: How the Human Eye Works (How Stuff Works) http://videos.howstuffworks.com/hsw/8195-investigating-human-biology-how-the- human-eye-works-video.htm

4. Rod & Cone Cells Rods and cones are cells in the retina that help your retina transmit the image. Rods are sensitive to light and dark, Rods are used for night vision. They are sensitive only to one color (deep violet). About 125 million rods Cones are sensitive to color. Cones come in three “types” (red, green, and blue). About 6 million cones

5. Vision Details & Facts In the human eye, there are many more rod cells in the retina than there are cone cells. The human eye can distinguish about 10 million different colors. The number of rod cells and cone cells in animals is often related to the animal's instincts and habits. For example, birds such as hawks have a significantly higher number of cones than do humans. This lets them to see small animals from a long distance away, allowing them to hunt for food. Nocturnal animals, on the other hand, have relatively higher numbers of rod cells to allow them better night vision.

6. Example: Human

7. Example: Monkey

8. Example: Owl

9. Human vs. Dog

10. Law of Reflection The girl in Edouard Manet's painting,The Bar at the Folies-Bergeres, is standing in front of a large plane mirror. Based on the law of reflection what is wrong with this painting? Answer: ________________ _______________________

11. Farsightedness: When the eyeball is too short, the image is formed behind the retina. People who have farsightedness see distant objects well, but do not see close objects well. A convex lens is used to correct.

12. Nearsightedness When the eyeball is too long, the image is formed in front of the retina. People who have nearsightedness see close objects well but do not see well in the distance. A concave lens is used to correct.

13. Vision Correction (not required for test) Glasses Contact Lenses Surgery There are a number of different kinds of surgeries available for correcting vision. Laser surgery is intended to reshape the cornea, or surface of the eye, in order to change how light rays are refracted. LASIK is the most popular form of laser surgery Bionic Eye (Tech Breakthrough: Bionic Eye) http://www.redorbit.com/news/video/technology/7/te ch_breakthrough_bionic_eye/28198/ http://www.redorbit.com/news/video/technology/7/te ch_breakthrough_bionic_eye/28198/

14. Vision Problems (not required for test) Conjunctivitis (Pink Eye) Glaucoma Macular Degeneration Keratoconus Macular Dystrophy Retinitis Pigmentosa Sun Protection For Your Eyes Your eyes can "burn" in the sun and cause disease later in life http://www.cbsnews.com/video/watch/?id=4140331nhttp://www.cbsnews.com/video/watch/?id=4140331n

15. Review Exploring Light and Color: Light and the Sense of Sight (How things Work) http://videos.howstuffworks.com/hsw/9941- exploring-light-and-color-light-and-the-sense-of- sight-video.htm http://videos.howstuffworks.com/hsw/9941- exploring-light-and-color-light-and-the-sense-of- sight-video.htm Name 8 parts of the eye What is responsible for helping see colors? Farsighted can see________ but not _____ Nearsighted can see _______ but not _____