Download Diseases and Disorders of the Eye and Ear

Chapter 5
Diseases and Disorders of the Eye and
Ear
Functioning Organs of Vision
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Vision requires:
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light stimulus
relay of light/image to the retina
stimulation of rods and cones in the retina
nerve impulses conducted to brain
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Normal Eye
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Functioning Organs of Vision (cont’d.)
Signs and symptoms that need medical
attention:
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visual disturbances
unequal pupils or sudden loss of vision
persistent pain
itching or burning in or around the eyes
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Functioning Organs of Vision (cont’d.)
Signs and symptoms that need medical
attention
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swollen, red eyelids
redness of the eyes
drainage or exudate
lesions/sores
involuntary eye movements
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Eye
Refractive Errors
 Hyperopia (Farsightedness)
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light focused behind the retina, which impairs near vision
Myopia (Nearsightedness)
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light focused in front of the retina, which impairs far vision
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Eye
Refractive Errors
 Astigmatism
• light focused unevenly onto the retina, which
causes blurred areas
 Presbyopia
• eye cannot focus quickly to accommodate
changes in distance
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Eye (cont’d.)
Nystagmus
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involuntary, repetitive, rhythmic movements of one
or both eyes
Strabismus
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failure of the eyes to look together in the same
direction
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Eyelid (cont’d.)
Conjunctivitis
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inflammation of the conjunctiva in one or both
eyes
Mucous discharge from the eye
can be caused by viral or bacterial infection
highly contagious
commonly called “pink eye”
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Globe of the Eye
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Cataracts
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cloudy area in the lens
opacity blocks light from reaching retina
usually develop slowly
gradual reduction of vision
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Globe of the Eye (cont’d.)
Glaucoma
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damage to the optic nerve caused by elevated
intraocular pressure
 open-angle vs. closed-angle
 One of the major cause of blindness
 more common after age 60, but can occur at any
age
 more common with nearsightedness
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Globe of the Eye (cont’d.)
Macular Degeneration
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progressive deterioration in retina
may start with mild distortion of central vision and
progress to complete loss
usually both eyes are affected
leads to central vision blindness
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Globe of the Eye (cont’d.)
Diabetic Retinopathy
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caused by small hemorrhages and newly formed
vessels in the retina
decreased visual clarity
usually both eyes are affected
major cause of blindness
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Globe of the Eye (cont’d.)
Retinal Detachment
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separation of the retina from the choroid
usually sudden and painless
early symptoms are seeing light flashes and
floaters
more common with nearsightedness
results in blindness if untreated
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Chapter 5
Lesson 5.2
Functioning Organs of Hearing
Hearing requires:
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vibratory or sound stimulus
relay of sound/vibration to inner ear
stimulation of tiny hairs in cochlea
nerve impulses conducted to brain
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Functioning Organs of Hearing (cont’d.)
Signs and symptoms that need medical
attention:
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hearing loss
ear pain or pressure
ringing or buzzing noise (tinnitus)
vertigo or dizziness
nausea and vomiting
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Disorders of the Ear
Disorders of Conduction
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impacted cerumen
infective otitis externa
swimmer’s ear
otitis media
otosclerosis
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Disorders of the Ear (cont’d.)
Infective Otitis Externa
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Inflammation of external ear canal with signs and
symptoms of:
• pain, often severe
• red, swollen canal
• fever
• itching
• drainage, watery or purulent
• hearing loss
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Ear (cont’d.)
Otitis Media
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Inflammation of the middle ear with signs and
symptoms of:
• feeling of fullness or pressure
• impaired hearing
• pain, often severe
• drainage, watery or purulent
• fever
• nausea and vomiting
• dizziness
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Ear (cont’d.)
Otitis Media
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Treatment includes:
• analgesics for pain relief
• decongestants to promote drainage
• antibiotics (for suppurative otitis)
• myringotomy: surgical removal of the fluid in severe
cases
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Disorders of the Ear (cont’d.)
Ménière Disease
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chronic disease of the inner ear
syndrome includes: vertigo, tinnitus, progressive hearing
loss and sensation of pressure
sudden onset of episodes (vertigo, tinnitus, etc.)
duration of hours to days
treatment is symptomatic relief, not curative
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Ear (cont’d.)
Labyrinthitis
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inflammation of labyrinth usually from viral or
bacterial infection; can result from meningitis
ruptured tympanic membrane
tear or injury resulting from pressure, untreated
middle ear infection, force or trauma
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.
Disorders of the Ear (cont’d.)
Sensorineural Hearing Loss
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nerve impulses not transmitted to the brain due to
damage to the cochlea or auditory nerve
hearing loss can result from loud music, industrial
noise, nearby explosion, medications, the aging
process, and certain other causes
irreversible, so prevention is essential
Elsevier items and derived items © 2009 by Saunders, an imprint of Elsevier Inc.