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Conjunctiva
- Transparent membrane that lines the eyelids
- Also located over white of eye on anterior surface
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Lysozyme
An enzyme that tears contain that inhibits growth of bacteria on surface of eye
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Orbit
Bony socket that provides protection from trauma
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Cranial nerves involved in movement of eye
- Oculomotor (III)
- Trochlear (IV)
- Abducens (VI)
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3 layers of wall of the eyeball
- Outer fibrous tunic (sclera and cornea)
- Middle vascular tunic (Choroid, ciliary body, iris)
- Inner nervous tunic (retina)
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Choroid layer contains what
blood vessels and melanin which prevents glare by absorbing light
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Two parts of eye that don't have capillaries
- Cornea (first part of eye that refracts light rays)
- Lens (permits focusing of light at varying distances)
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Contraction of radial fibers of iris
Is a sympathetic response and dilates the pupil
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Contraction of the circular fibers of iris
Is a parasympathetic response and constricts the pupil.
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The area of most acute color vision
Fovea centralis - contains only cones
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Retina
- Lines 2/3 of eyeball and contains rods and cones (photoreceptors)
- Rods: detect light
- Cones: Detects colors
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Neuron cells that transmit impulses generated by rods and cones
Ganglion cells
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Substance that keeps retina in place
- Vitreous humor
- Aqueous humor is the tissue fluid that nourishes the lens and cornea
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Where are the visual areas in the brain
- Occipital lobes of cerebral cortex
- Upside down images are uprighted and converged into one image (binocular vision)
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Most common changes in aging eye are located where
- Lens
- Loses elasticity, may become opaque
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Normal age related changes to eye
- Color vision fades
- Glare adaption difficult
- Decreased peripheral vision
- Decreased depth perception
- Increase in farsightedness
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Visual impairment occurs at ____?
Legal blindness occurs at____?
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Nystagmus
Involuntary, cyclical, rapid movement of eyes in response to vertical, horizontal, or rotary movement
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Tropia
- Movement of eye away from visual axis
- Estropia: movement toward nose
- Extropia: movement laterally
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Accomodation
- Ability of pupil to respond to near and far distances
- Normally, eyes turn inward and pupils constrict
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One of the most simple ways to improve vision for older adult
Make sure eyeglasses are clean
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Palpebral fissure
The distance between the upper and lower eyelid
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Arcus senilus
- Whitening of the outer rim of cornea.
- Considered normal and doesn't affect vision
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Optometrist vs. opthalmologist vs. optician
- Optometrist: Treatment of visual problems (glasses)
- Opthalmologist: diagnoses and treats eye diseases
- Optician: Grinds and fits lenses
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Diet and eyes
- Not enough Vit A: night blindness, corneal damage
- Not enough Vit B: Optic neuritis
- Obesity, high fat diet, low zinc: macular degeneration
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What kind of solution is used for eye irrigation
Isotonic
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Middle ear
- Contains eardrum that transmits vibrations through malleus, incus and stapes bones.
- The stapes then transmits vibrations to inner ear
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Inner ear
Contains receptors for hearing and equilibrium
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Auditory areas of brain
Temporal lobes of cerebral cortex
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Aging and the ear
- Damage to hair cells in organ of corti
- Presbycusis (high pitched range lost) caused by loss of hair cells and decreased blood supplying the ear.
- Inability to distinguish s, z, t, f, and g
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What disease is related to ear disorders
Meniere's disease
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Romberg's test
Test - patient stands with eyes closed. If there is swaying, it's positive and patient may have inner ear problem
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Caloric Test
Water is instilled into ear and if no nystagmus occurs, patient may have meniere's disease
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Hearing aids
- Postauricular - most common. Fits behind the ear.
- All in one eyeglasses aid - least common
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Treatment for someone who is profoundly deaf
Coclear implant. Converts sounds into electrical signals.
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Menieres disease diet
Low sodium. Increased fluid contributes to symptoms.
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Ringing in the ear
- May indicate that damage may be occurring
- Occupational noise is the primary cause of hearing loss
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Conjunctivitis
- Bacterial (pink eye) caused mostly by strep or staph.
- Very contagious
- Treated with antibiotic eyedrops
- Cipro to treat - give on empty stomach
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Blepharitis
- Chronic inflammation of eyelids
- Treatment: Long term daily cleansing
- If infection occurs, erythromycin or bacitracin to treat
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Hordeolum & Chalazion
- Hordeolum: external sty. No treatment unless doesn't heal
- Chalazion: Internal sty. May require surgical incision to treat
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Keratitis
- Inflammation of cornea.
- Herpes simplex keratitis is most common
- Wearing contacts overnight increases risk of pseudomonas pathogen
- S/S:Photophobia, blepharospasm, opaque cornea
- Serious and often sight threatening
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Hyperopia
- Farsightedness
- See images far better than close.
- Eyeball is too short.
- Corrected with convex lenses
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Myopia
- Nearsightedness
- Eyeball elongated
- See close better than far
- Corrected with concave lenses
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Astigmatism
Unequal curvatures of cornea
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Presbyopia
- Lenses lose elasticity
- Decrease in ability to focus on close objects
- Associated with aging and usually occurs after age 40
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Diabetic retinopathy
- 3 stages: Background, preproliferative and proliferative
- S/S: reduction is visual acuity or color vision
- Common to have no symptoms until proliferative stage
- Dx: exam of internal eye yearly if you have diabetes
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Retnal detachment
- Separation of retina from choroid
- 3 causes: tear in retina, fibrous tissue in vitreous, fluid accumulation in subretinal space
- S/S: sudden change in vision, flashing lights or floaters, progressing to curtain being lowered, no pain
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Primary open angle glaucoma
- Schlenm's canal degenerates and blocks flow of aqueous, Increase in IOP
- risk ↑ >40
- S/S: Develops bilaterally. Gradual, painless, halos around light, visual changes
- Isopto or Pilocar to constrict pupil. Diamox, propine, Timoptic to slow progression.
- Lifelong use of eyedrops
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Acute angle-closure glaucoma
- Occurs in people who have narrowed junction where iris meets cornea.
- Medical emergency , blindness if not treated
- Unilateral, rapid onset
- S/S: severe pain, blurred vision, rainbows around lights, photophobia
- Treatment: mannitol to reduce IOP, analgesics, complete bedrest.
- Mydriatics (atropine, benadryl) contra and may cause blindness
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Cataracts
- Opacity of lens
- S/S: painless, halos around lights, difficulty reading in bright light, ↓ color vision, blurring of vision
Treatment: removal of cloudy lens
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Macular degeneration
- Leading cause of visual impairment over 50
- Degeneration of macula.
- S/S: slow loss of near vision, dark or empty spot in center of vision, ↓ in color distinction
- No treatment for dry
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Conductive hearing loss
- Inner ear not involved
- Many causes may be corrected. Hearing devices are usually effective
- Causes: Otosclerosis, fluid, perforation of eardrum, foreign bodies
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Sensorineural hearing loss
- Originates in cochlea and involves hair cells and nerve endings
- Casues: Infections (measles, mumps, meningitis) drugs, noise, aging
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External otitis
- Most common infection of ear
- Staph is most common organism
- Swimmers ear when water left in ear
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When irrigating ear, what position do you put ear?
- Adults: Upward and back
- Children: Downward and back
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Otitis media
- Most common disease of middle ear
- S/S: fever, earache, feeling of fullness
- Complications: perforation of tympanic membrane (causes hearing loss), cholesteatoma, tympanosclerosis, mastoiditis
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Otosclerosis
- Formation of new bone along stapes that causes conductive hearing loss
- Hereditary
- No cure. Hearing aids to improve
- Stapedectomy is treatment of choice
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Meneiere's disease
- Balance disorder
- S/S: vertigo, hearing loss, tinnitus.
- Acute attacks occur 2-3 times yearly with eventual remission
- Avoid alcohol, caffeine and tobacco
- May be placed on methotrexate or given gentamicin injection
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Ototoxic Drugs
- Gentamicin
- Lasix (Furosemide)
- Vancomycin
- Quinidine
- Erythromycin
- Bumetanide
- Methotrexate
- Indomethacin
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