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