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1. List and describe ways by which good vision is beneficial.
- negative feedback, warning, "finding and getting 'goodies'", communication with others, learning, pleasure
2. Name the three main reasons for poor vision.
- poor focusing (scattering or improper refraction)
- improper amount of light
- poor processing of impulses (in the eye, visual pathways, or the brain)
3. Describe the effects of aging on the amount of light that can reach the retina and explain the significance of these changes.
- effects = decline in amount of light reaching
- decr. transparency of the conjunctiva, cornea, lens, and vitreous humor
- decr. size of the pupil
- need more light to see well
4. Describe the effects of aging on the sensitivity of the retina to light and explain the significance of these changes.
- effects = declining sensitivity to light
- decr. # of cones
- incr. irregularity of rods
- decr. # of processing neurons
- need more light to see well
5. Describe the effects of aging on color vision and describe effects from altered color vision.
- effects = decline in ability to see colors,
especially short wavelengths = purples, blues
- decr. # of cones
- decr. amount of light hitting the retina
- great decr. in amount of short wavelength (blue) light hitting the retina
- effects = less ability to distinguish colors or see in "blue" light
6. Describe age changes in adaptability to changes in light intensity and describe effects from altered adaptability to changing light intensity.
- age changes = decline in adaptability to
changes in light intensity
- decr. adaptability to changing from bright to dim light due to decr. size change in the pupil
- effects = slower and less complete adaptability -> problems with vision when light intensities change rapidly or frequently
7. Describe the effects of aging on light scattering and describe outcomes affecting vision.
- effects = increase in scattering
- from changes in the conjunctiva, cornea, lens, and vitreous
- outcomes = incr. glare = incr. light hitting wrong receptors (rods and cones)
8. Describe the effects of aging on visual acuity for near objects and describe effects from altered near visual acuity.
- effects = decline in visual acuity for near
- stiffer lens, flatter lens
- weaker ciliary muscle
- effects = farsightedness, problems with "close" vision or "close" work, need for glasses, bifocals, etc.
9. Describe the effects of aging on visual acuity for distant objects and describe effects from altered visual acuity for distant objects.
- effects = decline in visual acuity for distant
- decr. amount of light to activate the cones (which are in the fovea)
- decr. # of cones (which are in the fovea)
- effects = need for brighter light, glasses, bifocals, etc.
10. Describe the effects of aging on visual acuity during motion and describe effects from alteration in visual acuity of motion.
- effects = decline in visual acuity for moving
objects relative to stationary objects
- decr. smoothness of eye muscle movements
- incr. afterimages (slower neuron recovery)
- effects = problems with activities requiring good vision "in motion"
11. Describe the effects of aging on binocular vision and describe effects from altered binocular vision.
- effects = decline in binocular vision
- uneven aging of the two eyes -> incr. reliance on dominant eye
- decr. brain interpretation of different images from each eye
- effects = problems with depth perception
12. List the effects in changes in vision resulting from the age changes mentioned in Objectives 3-11.
13. List several ways by which vision among the elderly can be assisted or improved.
- (1) increase lighting, (2) decrease glare, (3) enlarge items, (4) increase contrast, (5) avoid close vision, (6) slow motions and objects, (7) use eyeglasses and contacts
14. Describe the effects of aging on defense mechanisms for the eye and describe effects from altered defense mechanisms.
- effects = decline in defense functions
- decr. corneal sensitivity to pain
- slower blink reflex
- decr. in lacrimal fluid production
- effect = incr. risk of injury
15. Describe the main reasons why the following eye diseases decrease vision: cataracts, age- related macular degeneration, glaucoma, diabetic retinopathy.
- cataracts = lens opacities (especially in
the center) -> decr. transparency and incr. scattering -> cloudy and foggy
- age-related macular degeneration = separation of macular region of the sensory retina from other layers (made worse by choroid hemorrhaging) -> decr. nutrition for the macula -> macular degeneration -> decr. central vision (including color vision)
- bleeding -> rapid macular blindness
- glaucoma = incr. intraocular pressure -> injury to retina and optic nerve -> limited field of view (tunnel vision), blindness
- diabetic retinopathy = damaged retinal capillaries -> retinal damage
- NOTE: bleeding into the vitreous -> blindness
- (sorbitol in mural cells -> mural cell swelling and injury -> capillary weakness) -> capillary hemorrhaging and narrowed capillaries (ischemia) -> damaged retina (with vessel proliferation into vitreous -> vitreous hemorrhaging -> retinal detachment &/or secondary glaucoma -> blindness)
For Internet images of normal eye structures or eye diseases, search the Images section of http://www.google.com/ for specific items (e.g., cataract). For diseases, I highly recommend searching WebPath: The Internet Pathology Laboratory .
16. Name the four types of stimuli monitored by the ears and name two benefits from monitoring these stimuli.
- stimuli = (1) sound, (2) gravity, (3) change
in speed, (4) rotation of head
- benefits = homeostasis, learning, communication, pleasure
17. Describe age changes in cerumen and describe effects from these changes.
- cerumen - becomes more viscous -> accumulation -> blockage of ear canal -> decr. hearing
18. Describe age changes in ability to hear; ability to hear different frequencies of sound; ability to localize sound; and ability to interpret sound; and give one effect from each change including biological, social, psychological, and economic examples.
- hearing - decr. hearing (from (1) decr. endolymph
and (2) decr. # of cells in and around the organ of Corti)
- frequencies - decr. in hearing higher frequencies (from (1) deterioration of the beginning area of the organ of Corti)
- localization - decr. ability to localize sound (from (1) unequal age changes between the two ears and (2) decr. processing and interpretation by the brain)
- interpretation - decr. interpretation (from decr. brain functioning)
- effects = decr. defense, decr. learning, decr. communication, decr. pleasure
19. List the four effects on a person's life style or quality of life that result from the age changes mentioned in Objective 18.
20. Define presbycusis, describe trends with aging in its incidence and severity, describe methods to prevent its occurrence, name methods to compensate when it occurs, and name effects from presbycusis including biological, social, psychological, and economic examples.
- presbycusis = serious decrease in hearing
- incr. incidence and incr. severity with incr. age
- prevention = avoid loud noise (music, occupational, recreational, entertainment)
- compensation = reduce background noise, speak slower and more clearly, use visual cues, repeat messages, ask for confirmation of information or message sent
- effects = decr. defense, decr. learning, decr. communication, decr. pleasure, social, psychological, economic effects
21. Define tinnitus and name two effects.
- tinnitus = hearing sound when there is no
- effects = annoying, disrupted sleep, interferes with hearing other sounds
22. Describe the effects of aging on the ability to detect gravity, changes in speed, and rotation, and describe effects from these age changes including biological, social, psychological, and economic examples.
- effects = decr. in detection of gravity,
changes in speed, and rotation
- from (1) decr. # of neurons and other cells in the utricle, saccule, and ampullae, (2) unequal aging in the utricle and saccule, (3) decr. in size of otoliths, (4) decr. in # of otoliths, (5) decr. auditory nerve neurons, (6) decr. processing and interpretation by the brain
- effects = dizziness, vertigo, decr. balance, incr. falls
23. List and briefly explain factors that increase the risk of falling and of being injured by a fall as age increases.
- incr. risk of falling and injury from (1) decr. ear functioning, (2) decr. vision, (3) decr. skin sensations, (5) decr. proprioceptor sensations, (6) decr. muscle strength, (7) incr. joint stiffness, (8) decr. reflexes, (9) decr. coordination, (10) thinner fat, (11) weaker bones, (12) weaker soft tissues (e.g., skin), (13) slower healing
24. List some ways of reducing the risk of falling for the elderly and explain why preventing falls is especially important for the elderly including biological, social, psychological, and economic examples.
- therefore, prevent falls, (e.g., remove hazards,
improve lighting, provide rails and grab bars)
- falls -> injury (e.g., fractures) and slower recovery (e.g., slower healing) -> increased and longer adverse effects and disability (e.g., immobility) -> increased number and severity of outcomes and complications from injuries from falls as age increases
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© Copyright 1999 - Augustine G. DiGiovanna - All rights reserved.
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