Domain 2 Module: Relevant Medical Information (10 test questions) Flashcards
the globe - Collects and absorbs; light rays so they can form a clear image on the retina - Outer layer o Conjunctive o Sclera o Cornea - Inner layer o Anterior chamber o Posterior chamber o vitreous
Orbit
thin, transparent membrane; lines the inside of the eyes/sclera; does not cover cornea
- Protective barrier (alerts for foreign bodies)
- Lubricates front of eye
- Indicates ocular/physical health
Conjunctiva
white part of the eye; dense; provides protection
- Maintains shape of globe
- Provides protection to inner structures
- Provides attachment points for extraocular muscles
Sclera
highly organized group of cells and proteins; contains no blood vessels; receives nourishment from tears
- Refract and transmit light
- Provides most of the eye’s optical power
- If cornea loses elasticity or is damaged, it won’t be able to function properly and blurred images will be transmitted to the
retina
Cornea
Space in front of cornea, but behind the iris; contains iris, trabecular meshwork, canal of schlemm
Anterior Chamber
Small space between back of iris and lens
Posterior Chamber
Clear fluid inside anterior and posterior chamber; provides nourishment and support
Aqueous Humor
Composed of ciliary muscle
Involved in controlling lens accommodation and IOP
Ciliary Body
– colored part of the eye
- Regulates light entering the eye
Iris
- hole in the middle of the iris
- Constricts in bright light
- Dilates in dim light
Pupil
- extends where iris meets the cornea
- Drains/filters the eye
Trabecular Meshwork
- located between the retina and sclera
- Nourishes retina
- Removes waste
- Contains many blood vessels and capillaries
Choroid
- Refracts and focuses light
- Helps create a sharp image on retina
- Can change shape
Lens
- Light sensitive nerve tissue
- Breaks down images into brightness, position, color, and movement
- Converts images into electrical signals and sends those signals to the brain
Retina
- Peripheral retina; active in low light
- Responsible for night vision
- Poor perception of color and detail
Rods
- Light receptor cells
- Active in high light and color
- Detects color and detail
Cones
- Central part of the retina
- Responsible for detecting color and fine detail
- Clear visual acuity
Macula
visual pathway; no photoreceptor cells; cannot process light
Optic Nerve
a. carries impulses for sight from the retina to the brain
b. each nerve fiber corresponds to specific parts of the retina
c. once information gets to the optic nerve, it gets sent to the brain via the Visual Pathway
d. damage in this area: loss of vision in affected eye
optic nerve/ optic pathway
a. where nasal fibers of each optic nerve cross
b. separates information from the right visual field and the left visual field
c. right half of the visual field goes to the left side of the brain
d. left half of the visual field goes to the right side of the brain
e. images projected on the retina are inverted
f. damage in this area: hemianopia: loss of half the visual field (temporal loss)
g. damage AFTER chiasm: temporal loss in one eye, nasal loss in the other
optic chiasm
a. contains visual cortex
b. info from each part of the retina is combined and interpreted
c. organized into layers and columns
d. responsible for vision and visual perceptions
e. damage in this area: temporal loss in one eye, nasal loss in the other
f. “macular sparring”: when the macula is left intact
occipital lobes
a. the area at the side of each cerebral hemisphere
b. contains major portions of optic radiations
c. complex visual analysis
1. allows for categorization of objects; “memory library” of images
temporal lobes
a. upper mid part of each cerebral hemisphere
b. responsible for body sensations
c. responsible for spatial information
Posterior Parietal Lobes
What it is:
- Progressive, degenerative damage to the central part of the retina
- Affects the cones
- Wet: abnormal blood vessel grow and leak under the macula
- Dry: degeneration of retina
Causes:
- Age
- Genetics
Functional implications
- Central acuity loss
- Blind spot
- Photophobia
- Pool color vision
- Normal peripheral vision
Adaptations:
- Eccentric viewing
- Magnification
- Large print
- Diffused less intense light
- Direct light
- Telescopes
- Tinted lenses
- CCVT
- Adjustable lighting
- Reduce/eliminate glare
- High contrast
Treatments:
- Wet: shots in the eye to stop the bleeding
functional implications o Central acuity loss o Blind spot o Photophobia o Pool color vision o Normal peripheral vision
ARMD
What it is: - Progressive: night blindness peripheral loss tunnel vision complete blindness - Degeneration of rods (light sensitive cells in retinal periphery) - Can be found in: Ushers and Lebers Causes: - Genetics Risk Factors: - Age (teens/young adults) - Gender (more common in males)
Functional implications
- Loss of peripheral vision
- Night blindness
- Tunnel vision
- Decreased acuity and depth perception
- Retinal scarring (causes spotty vision)
- Cataracts possible
- May be accompanied with myopia, cataracts, keratoconus
Adaptations:
- High illumination
- Reduce glare
- Absorptive lenses
- Prism glasses
- CCVT
- High contrast
- Teach organized search patterns
Treatments:
- None – take precautions to prevent retinal detachment
functional implications o Loss of peripheral vision o Night blindness o Tunnel vision o Decreased acuity and depth perception o Retinal scarring (causes spotty vision) o Cataracts possible o May be accompanied with myopia, cataracts, keratoconus
RP
What it is:
- Decrease in retinal blood vessel development in preemie babies
- Leads to bleeding, scarring, and detachment
- Can range from minimal damage to complete blindness
Causes:
- Low birthweight
- Born before 31 weeks
- High duration and administration of oxygen
Risk Factors:
- Low birthweight
- Born before 31 weeks
- Overall health of infant
Functional implications
- Decreased visual acuity
- Severe myopia
- Possible retinal detachment
- Spotty vision
- Strabismus
- Retinal scarring
- Field loss
- Possible glaucoma
Adaptations
- high illumination
- magnification
- telescopes
- CCTV
Treatments:
- Vitamin E therapy
- Cryotherapy
- Vitrectomy
- Some cases resolve themselves
functional implications o Decreased visual acuity o Severe myopia o Possible retinal detachment o Spotty vision o Strabismus o Retinal scarring o Field loss o Possible glaucoma
ROP
What it is:
• Collection of Eye disease that causes increased pressure in the eye because of blockage in the normal flow of fluid in the aqueous humor
• Damages optic nerve
Caused by: • Changes in the uveal tract • Trauma • Medication reaction • Surgery • Genetics
Risk factors: • 55+ • family history • diabetes • Race (higher prevalence in African American or native American)
Functional Implications: • Fluctuating vision – can lead to stress and fatigue • Tunnel vision • Peripheral field loss • Poor night vision • Photophobia • Difficulty seeing large objects in close range • Decreased sensitivity to contrast • Pain/headaches • Eye redness • Hazy cornea • Wide open pupil • Degeneration of optic disc • Poor spatial awareness
Adaptations: • Sunglasses, eye shades • Lamps with adjustable lighting • Reduce glare • Increase contrast • Magnifiers • CCVT
Treatment: • Eye drops • Surgery o Trabeculectomy – removing portion of trabecular meshwork to improve drainage o Iridotomy – laser creates hole in iris
functional implications o Fluctuating vision – can lead to stress and fatigue o Tunnel vision o Peripheral field loss o Poor night vision o Photophobia o Difficulty seeing large objects in close range o Decreased sensitivity to contrast o Pain/headaches o Eye redness o Hazy cornea o Wide open pupil o Degeneration of optic disc o Poor spatial awareness
Glaucoma
What it is:
- Diabetes can cause changes in blood vessels of the retina
- Causes hemorrhaging in the retina and vitreous
- Neuropathy in feet and hands
- Retinal detachment and full blindness possible
- Proliferative: formation of new blood vessels
- Non-proliferative: beginning stages, blood vessels become weak
Caused by:
- Diabetes
- Genetics
- Retinal hemorrhage
- Glaucoma
- Cataracts
- Optic neuropathy
Functional Implications:
- Sensitive to glare
- Double vision
- Lack of accommodation
- Fluctuating acuity
- Diminished color vision
- Defective visual fields
- Floaters
- Retinal detachment
- Neuropathy – unable to tactilely discriminate
Adaptations:
- Good lighting
- Good contrast
- Magnification
- Reduce glare
- Pay attention to diet
- Tinted lenses
- Take care of feet to prevent infections
- Wear comfortable well-fitting shoes at all times
- Avoid bending, lifting, straining, rapid movement – can affect DR
Treatment:
- Diet
- Insulin
- Surgery
o Vascular photocoagulation – abnormal/leaky blood vessels sealed/destroyed by light
o Retinal photocoagulation – laser used to destroy oxygen starved area of retina creating regressing of abnormal/weak blood vessel growth
functional implications o Sensitive to glare o Double vision o Lack of accommodation o Fluctuating acuity o Diminished color vision o Defective visual fields o Floaters o Retinal detachment o Neuropathy – unable to tactilely discriminate
Diabetic Retinopathy
What it is:
- Damage to the visual cortex (in the brain)
o Problem with how information is transmitted from the eye to the brain and how the brain interprets that information
- Ocular structures remain in tact
- Disorders associated with CP, epilepsy, hydrocephalus, learning disabilities, deafness
- Common with : optic nerve atrophy, optic nerve hypoplasia, retinal abnormalities
Causes:
- Lack of oxygen (anoxia) at birth
- Head injury
- Infections that affect nervous system
Functional implications
- Fluctuation in visual functioning
- Loss of ability to understand information the eye is giving you
- Visual neglect
- Eye may look normal
- Inattention to visual stimuli
- Preference of touch over vision
- Difficult with visual clutter or when things are too close together
- Difficult discriminating figure-ground
- May have more central vision, peripheral vision
- Light gazing
- Photophobia
- Slower processing/response time
- May easily become overwhelmed
- Inability to coordinate visual information with other senses
- Visual Midline Shift Syndrome- shift in concept of midline following stroke or TBI
Adaptations:
- High illumination – spotlighting/indirect lighting sources are beneficial for clarity
- Eliminate visual clutter
- Eliminate glare
- Routines
- Repetition
- Bright contrast
- Consistent visual cues
- Combination of reading media
- Determine which sensory system works best
- Prevent visual overload
- Provide simple images and tasks
- Encourage tactile exploration
- Demonstrate via hand-over-hand
- Eliminate distractions
- Yoked Prisms
Treatments:
- None
functional implications
o Fluctuation in visual functioning
o Loss of ability to understand information the eye is giving you
o Visual neglect
o Eye may look normal
o Inattention to visual stimuli
o Preference of touch over vision
o Difficult with visual clutter or when things are too close together
o Difficult discriminating figure-ground
o May have more central vision, peripheral vision
o Light gazing
o Photophobia
o Slower processing/response time
o May easily become overwhelmed
o Inability to coordinate visual information with other senses
o Visual Midline Shift Syndrome- shift in concept of midline following stroke or TBI
CVI
congenital abnormality; optic disc is small, sometimes surrounded with a halo; vision may or may not be reduced
Small optic cup. Usually results in low visual acuity. Additional cognitive disabilities often present. Frequent in children.
functional implications:
o Decreased visual acuity
o Additional cognitive disabilities often present
Optic Nerve Hypoplasia
progressive retinal degeneration in both eyes; night blindness in childhood followed by loss of peripheral vision to finally blindness; hereditary
functional implications
o Progressive decreased night vision
o Followed by central loss, color, and detail vision
Rod/Cone
degeneration of retinal receptors results in loss of color and central vision, followed by loss of night vision
functional implications
o Loss of central, color and detail vision first
o Followed by loss of night vision
Cone/Rod
malignant Intraocular tumor that develops from retinal & visual cells; hereditary; vision loss can be total or scotomic
functional implications
o If one eye – lack of depth perception and Field loss
o If both eyes – total blindness
Retinoblastoma
Farsightedness
functional implications
refractive ability too weak, eye is too sort, power must be increased to form a point on retina
o Inability to see close
o Blurred image on retina when viewing close objects
o May need to move objects farther from the eye for clear image
o If uncorrected
Brain receives poor, blurred image
Impacts development of the visual system
Reduced attention to objects at near
Hyperopia
Nearsightedness
functional implications
refractive ability too strong, eye too long; power must be taken away to form a point on retina
o Can’t see distance
o Blurred image on retina when viewing objects at a distance
o May need to bring object closer to eye for clear image
o If uncorrected:
Brain receives poor, blurred image
Impacts development of visual system
Visual world “collapses” – reduced/inattention to distant objects/activities
o May not be able to be fixed
Myopia
uneven focus of light between both eyes
functional implications
o Light rays entering the eye are bent unequally
o Prevents formation of a sharp image on the retina
o Inability of the eye to focus sharply at any distance
Astigmatism
What it is: - Gradual hardening of the lens elasticity Causes: - Age Functional implications - Reduced ability to accommodate Adaptations - Good lighting - High contrast Treatments: - none
functional implications
o Reduced ability to accommodate
o Affects the elderly
Presbyopia
OU
Both Eyes together
OD
Right eye
OS
Left eye
shows the quietest sounds you can just hear
Audiogram
a. strength of sound
b. amplitude
c. measured in decibels
d. measure of sound pressure level
e. relative strength of sound waves (transmitted vibrations), which we perceive as loudness or volume
Intensity
a. pitch
b. the rate of particle vibration measured in cycles per second
c. measured in Hertz
d. For sound, this means the number of pressure waves per second that would move past a fixed point. It is also the same as the number of vibrations per second the particles are making as they transmit the sound.
Frequency
portion of a particle in its vibrating cycle
Phase
a. sensation of frequency
b. high pitch = high frequency
c. relates to the frequency, or how many times a second the particles vibrate. The distance between one wave and the next gives the wavelength. For sounds all travelling at the same speed, high-frequency sounds have waves very close together. Low-frequency sounds have a greater distance between each wave.
Pitch
a. unit used to measure the intensity of a sound or power level of electrical signal by comparing it with a given level on a logarithmic scale
b. not linear
Decibel
air conduction test unmasked left ear
X
air conduction test unmasked Right ear
O
bone conduction test right ear
<
bone conduction test Left ear
>
affecting both sides
bilateral
o dysfunction of the outer/middle ear
o usually treated with medication/surgery
o loudness deficit
o functional implications
soft speaking voice (they hear their voice louder than normal)
excellent speech discrimination when speech is loud enough
lower frequencies tend to be affected
temporary
conductive hearing loss
o dysfunction of the inner ear/auditory nerve
o usually permanent
o untreatable
o loudness deficit
o distorted hearing – nerve endings in the cochlea/nerve pathways damaged; messages do not effectively reach the brain
o middle ear structures in tact
o functional implications
inappropriately loud voice
tinnitus
frequency loss – high frequency (most common)
speech sounds distorted
background noise makes listening more difficult
hearing aids may help
• Hearing aids, cochlear implants, and other listening devices are notorious for distorting, changing, and generally making sounds unusable for orientation and mobility tasks. Many assistive devices are designed and set to enhance the human voice for communication, not to retrieve environmental sounds. In fact, they may be intentionally blocking distal environmental input. Also, no assistive listening device can reach far into the environment (such as hearing a car 300 feet away).
vertigo
gradual deterioration
difficulty distinguishing near vs. far (location acuity loss)
specific sounds seem unnaturally loud
difficulty understanding speech patterns
sensorineural hearing loss
combo of conductive and sensorineural hearing loss
treatment may be available for the conductive loss
both high and low frequency losses
Mixed hearing loss
help people with communication disorders to express themselves. These devices can range from a simple picture board to a computer program that synthesizes speech from text.
augmented communication (def.)
If the bone conduction hearing thresholds are normal, but there is a loss of hearing for air conduction sounds, this is called a
conductive hearing loss
When there is no difference between the air conduction and the bone conduction thresholds it indicates that the hearing loss is due to a problem in the cochlea.
sensorineural hearing loss
gap between the air conduction and the bone conduction thresholds, however the bone conduction thresholds still indicate a hearing loss as they are not within normal limits. This would suggest that there is a problem in both the cochlear and the middle ear
mixed hearing loss
-10 to 15 dB HL → normal hearing
16 to 25 dB HL→ slight hearing loss
26 to 40 dB HL→ mild hearing loss
41 to 55 dB HL→ moderate hearing loss
56 to 70 dB HL→ moderately severe hearing loss
71 to 90 dB HL→ severe hearing loss
>90 → profound hearing loss
Classification of Hearing Impairment
What eye diseases are associated with diabetes?
a. Diabetic Retinopathy
b. Glaucoma
c. Cataracts
a. Monitor blood sugar and note instances of low/high
b. Lethargy
c. Neuropathy
i. Hands- make it difficult to get feedback from cane
ii. Feet – make it difficult to detect drop offs
d. Rapid changes in vision likely
i. Bad vision days make indicate low blood sugar
e. Pressure sores common
i. Wear comfortable sneakers
ii. Monitor for pain, swelling, bruising, blistering, tenderness, discoloration of the skin
f. Keep a diabetic information sheet
i. Student name, address, phone number
ii. School/agency name, address phone number
iii. Doctor name and phone number
iv. Emergency contact
v. Type of insulin, amount taken, time of day given
vi. Typical symptoms of student and how student wants to handle them
vii. Time of day likely to have reaction
the considerations when developing an O&M instruction program for persons with diabetes?
a. CMV (cytomegalovirus):
b. Kaposi’s sarcoma
c. Toxoplasmosis
d. Cryptococcal meningitis
e. Central nervous system infections
f. HIV retinopathy
eye diseases that are associated with AIDS
a. Decreased functioning of immune system can lead to neurological complications
b. Prevent yourself from becoming infected
c. Practice good hygiene
d. Reschedule if you are sick
e. Practice “universal health precautions”
f. Students willingness and ability to participate may vary from day to day or even hour to hour
g. Confirm all meetings several hours before appointment
h. Goals may need to be reassessed and modified as students physical condition changes
i. Because of privacy las, you may not know if a student has HIV/AIDS and it might be difficult to accurately plan lessons and goals
j. Vision impairment comes in the later stages
implications of AIDS for O&M instruction?
What should an O&M specialist do if a client has a hypoglycemic reaction or a hyperglycemic reaction during an O&M lesson?
Hypoglycemic: give fruit drink/sugar
Hyperglycemic: insulin
