Caring for Your Eyes

1. Caring for YourEyes Lesson 3.4

2. OBJECTIVES • How to keep your eyes healthy • Anatomy of the eye • Explain how the eye works. • Disorders of the Eyes

3. The pupil is the dark part of the eye. Controls the amount of light that enters the eye. • The colored part of the eye is the iris. Heredity determines the IRIS color. • The cornea is the clear section that lets in light at the front of the eye. • Lens- focuses the light on the retina • Sclera- the white of the eye. It covers and protects the whole eye, except for the front. • Optic Nerve- Bundle of nerve fibers that send messages to the brain, which interprets them. • Retina- the light sensing part of the inner eye.

4. Eyes are amazing things. • Our eyelid is like a windshield on a car, it cleans your eyeball when you blink. • When it is dark the eye opens wider to let more light in. When it is light the eye protects itself by only letting a little light in. • Eye lets you see millions of colors. • Eye lets you see close and far away. • In fact almost everything you learn you can learn by seeing.

5. How The Eye Works • Like a camera, the eye takes in light and focuses it to create an image. • Image is sent to the brain which develops the picture. • Image enters the eye and optic nerve upside-down and then are corrected by the brain.

6. *We see color with the sensors in the retina of the eye called rods and cones. The rods are sensitive to low light and the cones, which require a greater intensity of light, are sensitive to color. The message is passed to the optic nerve and then on to the brain. * There are about 120 million rods and about 6 to 7 million cones, in the human eye.

7. RODS • Rods are more sensitive than the cones but they are not sensitive to color, they perceive images as black, white and different shades of grey.

8. CONES • Each cone contains one of three pigments sensitive to either RED GREEN or BLUE. • When we observe a color that has a wavelength between that of the primary colors red, green and blue, combinations of the cones are stimulated. An example could be that yellow light stimulates cones that are sensitive to red and to green light. • People who suffer color blindness have less numbers of particular cones than normal, so they get colors confused

9. Color Blind Test

10. Disorders of The Eye

11. Nearsighted Image

12. Farsighted Image

13. Our Eye Helps Us Memorize Things. • One way to memorize is to make a picture in our minds of what we are trying to remember. • You have one minute to memorize these objects.

14. We Have Only 1 Nose and 1 Mouth. Why Do You Think We Have 2 Eyes? • The brain takes the picture seen by each eye and combines them to make one picture. ( 3D Images) • Sometimes our brain is tricked • into seeing things that aren’t real. • These are called optical illusions. • Let’s try some!

15. What Do You See?

16. What Do You See?

18. How Many Prongs Are on This Fork?

19. Find the Secret Message

20. What Do You Think You See?

21. What Does This Say?Now Read It Again!

22. Famous Painting

24. Which Line Is Longer?

25. Stare at the image for 20 seconds and then look at a white piece of paper.

26. Stare at the dot in the middle of the circle. What happens?

27. Stare at the center. What happens to the gray?

28. Stare at the image for 30 sec, then look at a white piece of paper and see the colors change.

29. Caring for Your Eyes • Make sure you have enough light while reading and watching TV. • Outside wear sunglasses • Don’t rub your eyes ( wash out) • Wear protective equipment when playing sports and working with power tools. • Have your eyes examined regularly by an Optometrist- ( examine and prescribe glasses) • Ophthalmologist- Physician who specializes in the structure, functions, and diseases of the eye.