1. Light and Sight What do you see when you look at the pictures above?

2.  Identify the parts of the human eye and describe their functions  Describe three common vision problems  Escribe surgical eye correction TIC identify the parts of the human eye and describe their functions.

3. Parts of the Human Eye Cornea: a membrane that protects the eye. Light is refracted as it passes through the cornea. Pupil: the opening in the eye. Light passes through it. Iris: controls the size of the pupil. It is the colored part of the eye. Lens: convex shape … it refracts light to focus a real image on the back of the eye.

4. Parts of the Human Eye Retina: the back surface of the eye. Light is detected by receptors in the retina called rods & cones. Rods detect very dim light Cones detect colors and bright light Nerves attached to the rods and cones carry information to the brain about the light that strikes the retina.

5. Parts of the Human Eye p. 674

6. How the Human Eye Works

7. Common Vision Problems Nearsightedness: a condition in which the lens of the eye focuses distant objects in front of rather on the retina. o People who are nearsighted can see things clearly when they are nearby. o Nearsightedness happens when a person’s eye is too long.

8. Common Vision Problems Farsightedness: a condition in which the lens of the eye focuses distant objects behind rather than on the retina o People who are farsighted can see faraway objects clearly. o Farsightedness happens when a person’s eye is too short.

9. Common Vision Problems p. 675

10. Common Vision Problems Color Deficiency, or Colorblindness, happens when the cones in the retina do not work properly. People who are colorblind cannot see all of the colors of visible light. The three kinds of cones are named for the colors they detect most – red, green, or blue. 5-8% of men and 0.5% of women are colorblind. Most of the people who are colorblind cannot tell the difference between red and green.

11. Colorblindness p. 676 https://www.yo utube.com/wa tch?v=CWyrp3 hu4KE

12. Surgical Eye Correction Surgery can be used to correct vision problems. Surgical eye correction reshapes the patient’s cornea that changes how light is focused on the retina Problems: can lead to seeing glares, having double vision, having trouble seeing at night, or losing vision permanently. People < 20 years old should not have surgical eye correction because their vision is still changing.

13. Surgical Eye Correction https://www.yo utube.com/wat ch?v=TL4m7cP YyUY

14. Exit Ticket : see p. 674 1.Draw an eyeball for your notes. 2.Include all the important parts (blue lines)