Chapter 5 Diseases and Disorders of the Eye and Ear

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Chapter 5Diseases and Disorders of the Eye and
Ear
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Functioning Organs of Vision

• Vision requires
• light stimulus
• relay of light/image to the retina
• stimulation of rods and cones in the retina
• nerve impulses conducted to brain

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Normal Eye
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Functioning Organs of Vision (contd.)

• Signs and symptoms that need medical attention
• visual disturbances
• unequal pupils or sudden loss of vision
• persistent pain
• itching or burning in or around the eyes

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Functioning Organs of Vision (contd.)

• Signs and symptoms that need medical attention
• swollen, red eyelids
• redness of the eyes
• drainage or exudate
• lesions/sores
• involuntary eye movements

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Disorders of the Eye

• Refractive Errors
• Hyperopia (Farsightedness)
• light focused behind the retina, which impairs
  near vision
• Myopia (Nearsightedness)
• light focused in front of the retina, which
  impairs far vision

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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

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Disorders of the Eye (contd.)

• Nystagmus
• involuntary, repetitive, rhythmic movements of
  one or both eyes
• Strabismus
• failure of the eyes to look together in the same
  direction

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Disorders of the Eyelid (contd.)

• Conjunctivitis
• 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

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Disorders of the Globe of the Eye

• Cataracts
• cloudy area in the lens
• opacity blocks light from reaching retina
• usually develop slowly
• gradual reduction of vision

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Disorders of the Globe of the Eye (contd.)

• Glaucoma
• 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

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Disorders of the Globe of the Eye (contd.)

• Macular Degeneration
• 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

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Disorders of the Globe of the Eye (contd.)

• Diabetic Retinopathy
• caused by small hemorrhages and newly formed
  vessels in the retina
• decreased visual clarity
• usually both eyes are affected
• major cause of blindness

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Disorders of the Globe of the Eye (contd.)

• Retinal Detachment
• 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

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Chapter 5Lesson 5.2
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Functioning Organs of Hearing

• Hearing requires
• vibratory or sound stimulus
• relay of sound/vibration to inner ear
• stimulation of tiny hairs in cochlea
• nerve impulses conducted to brain

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Functioning Organs of Hearing (contd.)

• Signs and symptoms that need medical attention
• 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
• impacted cerumen
• infective otitis externa
• swimmers ear
• otitis media
• otosclerosis

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Disorders of the Ear (contd.)

• Infective Otitis Externa
• Inflammation of external ear canal with signs and
  symptoms of
• pain, often severe
• red, swollen canal
• fever
• itching
• drainage, watery or purulent
• hearing loss

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Disorders of the Ear (contd.)

• Otitis Media
• 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

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Disorders of the Ear (contd.)

• Otitis Media
• 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 (contd.)

• Ménière Disease
• 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

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Disorders of the Ear (contd.)

• Labyrinthitis
• 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

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Disorders of the Ear (contd.)

• Sensorineural Hearing Loss
• 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