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Chapter 5 Chapter 5 Diseases and Disorders of the Diseases and Disorders of the Eye and Ear Eye and Ear
Chapter 5Chapter 5Diseases and Disorders of the Eye and Diseases and Disorders of the Eye and
EarEar
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Functioning Organs of VisionFunctioning Organs of Vision
Vision requires:Vision requires: light stimuluslight stimulus relay of light/image to the retinarelay of light/image to the retina stimulation of rods and cones in the retinastimulation of rods and cones in the retina nerve impulses conducted to brainnerve impulses conducted to brain
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Normal EyeNormal Eye
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Signs and symptoms that need medical Signs and symptoms that need medical attention:attention: visual disturbances visual disturbances unequal pupils or sudden loss of visionunequal pupils or sudden loss of vision persistent pain persistent pain itching or burning in or around the eyesitching or burning in or around the eyes
Functioning Organs of Vision Functioning Organs of Vision (cont’d.)(cont’d.)
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Signs and symptoms that need medical Signs and symptoms that need medical attentionattention
swollen, red eyelidsswollen, red eyelids redness of the eyesredness of the eyes drainage or exudatedrainage or exudate lesions/soreslesions/sores involuntary eye movementsinvoluntary eye movements
Functioning Organs of Vision Functioning Organs of Vision (cont’d.)(cont’d.)
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Disorders of the EyeDisorders of the Eye
Refractive ErrorsRefractive Errors Hyperopia (Farsightedness)Hyperopia (Farsightedness)
light focused behind the retina, which impairs near visionlight focused behind the retina, which impairs near vision Myopia (Nearsightedness)Myopia (Nearsightedness)
light focused in front of the retina, which impairs far visionlight focused in front of the retina, which impairs far vision
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Refractive Errors Refractive Errors AstigmatismAstigmatism
• light focused unevenly onto the retina, which light focused unevenly onto the retina, which causes blurred areascauses blurred areas
PresbyopiaPresbyopia• eye cannot focus quickly to accommodate eye cannot focus quickly to accommodate
changes in distancechanges in distance
Disorders of the EyeDisorders of the Eye
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Disorders of the Eye Disorders of the Eye (cont’d.)(cont’d.)
NystagmusNystagmus involuntary, repetitive, rhythmic movements of one involuntary, repetitive, rhythmic movements of one
or both eyesor both eyes
StrabismusStrabismus failure of the eyes to look together in the same failure of the eyes to look together in the same
direction direction
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Disorders of the Eyelid Disorders of the Eyelid (cont’d.)(cont’d.)
ConjunctivitisConjunctivitis inflammation of the conjunctiva in one or both inflammation of the conjunctiva in one or both
eyeseyes Mucous discharge from the eyeMucous discharge from the eye can be caused by viral or bacterial infectioncan be caused by viral or bacterial infection highly contagioushighly contagious commonly called “pink eye”commonly called “pink eye”
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CataractsCataracts cloudy area in the lenscloudy area in the lens opacity blocks light from reaching retinaopacity blocks light from reaching retina usually develop slowlyusually develop slowly gradual reduction of visiongradual reduction of vision
Disorders of the Globe of the EyeDisorders of the Globe of the Eye
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GlaucomaGlaucoma damage to the optic nerve caused by elevated damage to the optic nerve caused by elevated
intraocular pressureintraocular pressure open-angle vs. closed-angleopen-angle vs. closed-angle One of the major cause of blindnessOne of the major cause of blindness more common after age 60, but can occur at any more common after age 60, but can occur at any
ageage more common with nearsightednessmore common with nearsightedness
Disorders of the Globe of the Eye Disorders of the Globe of the Eye (cont’d.)(cont’d.)
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Macular DegenerationMacular Degeneration progressive deterioration in retinaprogressive deterioration in retina may start with mild distortion of central vision and may start with mild distortion of central vision and
progress to complete lossprogress to complete loss usually both eyes are affectedusually both eyes are affected leads to central vision blindnessleads to central vision blindness
Disorders of the Globe of the Eye Disorders of the Globe of the Eye (cont’d.)(cont’d.)
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Diabetic RetinopathyDiabetic Retinopathy caused by small hemorrhages and newly formed caused by small hemorrhages and newly formed
vessels in the retinavessels in the retina decreased visual claritydecreased visual clarity usually both eyes are affectedusually both eyes are affected major cause of blindnessmajor cause of blindness
Disorders of the Globe of the Eye Disorders of the Globe of the Eye (cont’d.)(cont’d.)
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Retinal DetachmentRetinal Detachment separation of the retina from the choroidseparation of the retina from the choroid usually sudden and painlessusually sudden and painless early symptoms are seeing light flashes and early symptoms are seeing light flashes and
floatersfloaters more common with nearsightednessmore common with nearsightedness results in blindness if untreatedresults in blindness if untreated
Disorders of the Globe of the Eye Disorders of the Globe of the Eye (cont’d.)(cont’d.)
Chapter 5Chapter 5Lesson 5.2Lesson 5.2
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Functioning Organs of HearingFunctioning Organs of Hearing
Hearing requires:Hearing requires: vibratory or sound stimulusvibratory or sound stimulus relay of sound/vibration to inner earrelay of sound/vibration to inner ear stimulation of tiny hairs in cochleastimulation of tiny hairs in cochlea nerve impulses conducted to brainnerve impulses conducted to brain
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Signs and symptoms that need medical Signs and symptoms that need medical attention:attention: hearing losshearing loss ear pain or pressureear pain or pressure ringing or buzzing noise (tinnitus)ringing or buzzing noise (tinnitus) vertigo or dizzinessvertigo or dizziness nausea and vomitingnausea and vomiting
Functioning Organs of Hearing Functioning Organs of Hearing (cont’d.)(cont’d.)
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Disorders of the EarDisorders of the Ear
Disorders of ConductionDisorders of Conduction impacted cerumenimpacted cerumen infective otitis externainfective otitis externa swimmer’s earswimmer’s ear otitis mediaotitis media otosclerosisotosclerosis
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Disorders of the Ear Disorders of the Ear (cont’d.)(cont’d.)
Infective Otitis ExternaInfective Otitis Externa Inflammation of external ear canal with signs and Inflammation of external ear canal with signs and
symptoms of: symptoms of: • pain, often severepain, often severe• red, swollen canal red, swollen canal • fever fever • itchingitching• drainage, watery or purulentdrainage, watery or purulent• hearing losshearing loss
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Disorders of the Ear Disorders of the Ear (cont’d.)(cont’d.)
Otitis MediaOtitis Media Inflammation of the middle ear with signs and Inflammation of the middle ear with signs and
symptoms of:symptoms of:• feeling of fullness or pressure feeling of fullness or pressure • impaired hearingimpaired hearing• pain, often severepain, often severe• drainage, watery or purulentdrainage, watery or purulent• fever fever • nausea and vomitingnausea and vomiting• dizziness dizziness
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Disorders of the Ear Disorders of the Ear (cont’d.)(cont’d.)
Otitis MediaOtitis Media Treatment includes:Treatment includes:
• analgesics for pain reliefanalgesics for pain relief• decongestants to promote drainagedecongestants to promote drainage• antibiotics (for suppurative otitis)antibiotics (for suppurative otitis)• myringotomy: surgical removal of the fluid in severe myringotomy: surgical removal of the fluid in severe
casescases
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Disorders of the Ear Disorders of the Ear (cont’d.)(cont’d.)
Ménière DiseaseMénière Disease chronic disease of the inner earchronic disease of the inner ear syndrome includes: vertigo, tinnitus, progressive hearing syndrome includes: vertigo, tinnitus, progressive hearing
loss and sensation of pressureloss and sensation of pressure sudden onset of episodes (vertigo, tinnitus, etc.)sudden onset of episodes (vertigo, tinnitus, etc.) duration of hours to days duration of hours to days treatment is symptomatic relief, not curativetreatment is symptomatic relief, not curative
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Disorders of the Ear Disorders of the Ear (cont’d.)(cont’d.)
LabyrinthitisLabyrinthitis inflammation of labyrinth usually from viral or inflammation of labyrinth usually from viral or
bacterial infection; can result from meningitisbacterial infection; can result from meningitis ruptured tympanic membraneruptured tympanic membrane tear or injury resulting from pressure, untreated tear or injury resulting from pressure, untreated
middle ear infection, force or traumamiddle ear infection, force or trauma
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Disorders of the Ear Disorders of the Ear (cont’d.)(cont’d.)
Sensorineural Hearing LossSensorineural Hearing Loss nerve impulses not transmitted to the brain due to nerve impulses not transmitted to the brain due to
damage to the cochlea or auditory nervedamage to the cochlea or auditory nerve hearing loss can result from loud music, industrial hearing loss can result from loud music, industrial
noise, nearby explosion, medications, the aging noise, nearby explosion, medications, the aging process, and certain other causesprocess, and certain other causes
irreversible, so prevention is essentialirreversible, so prevention is essential
