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 (becomes smaller)
- Dilates in dim light (becomes larger)
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 in tact
occipital lobes
a. the area at the side of each cerebral hemisphere
b. contains major portions of optic radiations
c. complex visual analysis
i. allows for categorization of objects; “memory library” of images
5. posterior parietal lobes
a. upper mid part of each cerebral hemisphere
b. responsible for body sensations
c. responsible for spatial information
i. right parietal lobe – understanding spatial aspects of the world, recognizes shapes, being aware of ones body in space
temporal 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
Considerations for older adults with ARMD:
- Rehab interventions can affect coping mechanisms related to psychological adjustment
- Age related visual impairment can be linked to functional impairments, specifically in instrumental activities in daily living (getting dressed, eating, appearance)
- Successful adaptations to visual impairments may affect perception of older adults’ functional disabilities
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
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
Adaptations
- high illumination
- magnification
- telescopes
- CCTV
Treatments:
- Vitamin E therapy
- Cryotherapy
- Vitrectomy
- Some cases resolve themselves
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
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
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
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
Diabetic Retinopathy
abnormal/leaky blood vessels sealed/destroyed by light
Vascular photocoagulation
laser used to destroy oxygen starved area of retina creating regressing of abnormal/weak blood vessel growth
Retinal photocoagulation
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 CVI: CP, epilepsy, hydrocephalus, learning disabilities, deafness
- Common with CVI: optic nerve atrophy, optic nerve hypoplasia, retinal abnormalities
Causes:
- Lack of oxygen (anoxia) at birth
- Head injury
- Infections that affect nervous system
Functional implications (depends on type of CVI)
- 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
CVI
optic disc is small, sometimes surrounded with a halo; vision may or may not be reduce
congenital abnormality
Usually results in low visual acuity. Additional cognitive disabilities often present. Frequent in children.
Small optic cup
progressive retinal degeneration in both eyes; night blindness in childhood followed by loss of peripheral vision to finally blindness; hereditary
Rod/Cone
degeneration of retinal receptors results in loss of color and central vision, followed by loss of night vision
Cone/Rod: