1. Guided Reading Activity 52 Eye Care
Chapter 14, Lesson 3
Guided Reading Activity 52
Eye Care

2. 1. What percentage of sensory information your brain receives comes by way of your eyes?
More than 70%.

3. 2. What is the function of the eyes?
To gather light.

4. 3. What controls the amount of light that enters the eye?
The size of the pupil.

5. 4. Describe the function of each of the following:

6. 4a. Orbits
Boney sockets
Hold eyes in place

7. 4b. Layer of fat surrounding each eyeball
Cushions the eye ball inside the socket.

8. 4c. Eyebrows, eyelashes, and eyelids
Protect the eyes from foreign particles and bright lights.

9. 4d. Lacrimal gland
Secrets tears into ducts that empty into the eye.

10. 4e. Tears.
Keep surface of eye moist.
Clear of foreign particles.

11. 5. What are the two main parts of the eye?
The optic nerve
The eyeball wall

12. 6. List the function of the following parts of the eye.

13. a. Sclera The white of the eye Protects inner layers of the eye.
Supports and shapes the eyeball.
Sclera

14. b. Cornea Bends and focuses light before it enters the lens.

15. c. Choroid Lines the inside of the sclera.
Contains blood vessels which nourish the eye.
Choroid-----

16. d. Iris Muscles of the iris control the size of the pupil.
Give eye color.
Iris

17. e. Pupil
Allows light to reach the inner eye.
Pupil

18. f. Retina Allows images to be cast by the cornea.

19. g. Rods
Allows us to see in dim light.
Black and white.

20. h. Cones
Allow us to see color.

21. i. Lens
Refines the focus of images on the retina.
Lens

22. j. Aqueous humor Provides nutrients to the structures of the eye.

23. k. Vitreous humor. Helps the eyeball stay firm.

24. 7. List four health behaviors you can practice every day to keep your eyes healthy.
Eat a well balanced diet.
Protect your eyes.
Rest your eyes regularly
Have regular eye exams

25. 8. Explain the difference between myopia and hyperopia.
Hyperopia—Farsightedness
Person can see far
Close objects appear blurry.
Myopia—Nearsightedness
Person cannot see far.
Person can see close
Compare the shape of the eyeball

26. 9. Describe the following vision problems and eye diseases.

27. 9a. Astigmatism Cornea or lens is irregularly curved.
Makes images appear blurry.

28. 9b. Strabismus Muscles of the eyes appear weak.
Cause one or both eyes to move off center.
Cross-eye:
Eyes pull towards the nose.
Wall-eye
Eye (s) pull away from the nose.

29. 9. Colorblindness
Red-green color blindness is very common among males, affecting approximately 7% of the male population.  It is much less common in females, affecting less than 1%.

30. 9. Colorblindness

31. 9. Colorblindness

32. 9. Colorblindness

33. 9. Colorblindness
Red-green color blindness is very common among males, affecting approximately 7% of the male population.  It is much less common in females, affecting less than 1%.
If we have 400 students in our high school, with 250 males and 150 females, determine how many students in our school may be colorblind using the above information.

34. MATH PROBLEM ANSWER 250 X .07 = 17.5 150 X .01 = 1.5
= 19 Students

35. 9c. Glaucoma:
Pressure inside the eye is abnormally high leading to irreversible damage of the retina and optic nerve.
Can cause vision loss.

36. 9d. Cataracts:
The lens becomes cloudy.

37. 9. Cataracts:
Surgery

38. 9e. Macular degeneration
Light sensing cells in portion of the retina directly opposite the lens begin to malfunction.
It can cause vision loss.

39. Macular degeneration
The Amsler Grid is often used to monitor diseases affecting the retina, especially macular degeneration.  Any abnormal area in the grid, or any change in its appearance should be checked with an eye examination on an urgent basis.

40. 10. Describe three other diseases of the eye.
Sty
Swelling of a sebaceous gland near the eyelash.
Conjunctivitis--Pinkeye
Inflammation of the thin membrane that covers the sclera lining of the eyelids.
Detached retina
Portion of the retina separates from the choroid.