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
Conjunctive
Sclera
Cornea
Inner layer
Anterior chamber
Posterior chamber
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 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
carries impulses for sight from the retina to the brain
each nerve fiber corresponds to specific parts of the retina
once information gets to the optic nerve, it gets sent
to the brain via the Visual Pathway
damage in this area: loss of vision in affected eye
optic pathway
where nasal fibers of each optic nerve cross
separates information from the right visual field and the left visual field
right half of the visual field goes to the left side of the brain
left half of the visual field goes to the right side of the brain
images projected on the retina are inverted
damage in this area: hemianopia: loss of half the visual field (temporal loss)
damage AFTER chiasm: temporal loss in one eye, nasal loss in the other
Optic Chiasm
contains visual cortex
info from each part of the retina is combined and interpreted
organized into layers and columns
responsible for vision and visual perceptions
damage in this area: temporal loss in one eye, nasal loss in the other
“macular sparring”: when the macula is left in tact
Occipital Lobes
the area at the side of each cerebral hemisphere
contains major portions of optic radiations
complex visual analysis
allows for categorization of objects; “memory library” of images
Temporal Lobes
upper mid part of each cerebral hemisphere
responsible for body sensations
responsible for spatial information
right parietal lobe – understanding spatial aspects of the world, recognizes shapes, being aware of ones body in space
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
Considerations for older adults with
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
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
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
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
Trabeculectomy – removing portion of trabecular meshwork to improve drainage
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
Vascular photocoagulation – abnormal/leaky blood vessels sealed/destroyed by light
Retinal photocoagulation – laser used to destroy oxygen starved area of retina creating regressing of abnormal/weak blood vessel growth
Diabetic Retinopathy
What it is:
Damage to the visual cortex (in the brain)
Problem with how information is transmitted from the eye to the brain and how the brain interprets that information.
Ocular structures remain intact.
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
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.
Optic Nerve hypoplasia
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
malignant Intraocular tumor that develops from retinal & visual cells; hereditary; vision loss can be total or scotomic
Retinoblastoma
Farsightedness
Hyperopia
Nearsightedness
Myopia
uneven focus of light between both eyes
Astigmatism
What it is:
Gradual hardening of the lens elasticity
Causes:
Age
Functional implications
Reduced ability to accommodate
Adaptations
Good lighting
High contrast
Presbyopia
Central acuity loss
Blind spot
Photophobia
Pool color vision
Normal peripheral vision
ARMD
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
RP
Decreased visual acuity
Severe myopia
Possible retinal detachment
Spotty vision
Strabismus
Retinal scarring
Field loss
Possible glaucoma
ROP