Eye Assessment Flashcards
Palpebral fissure
the elliptical open space between the eyelids
limbus
the border between the cornea and sclera
Canthus
corner of the eye, the angle where the lids meet
Caruncle
a small, fleshy mass containing sebaceous glands
conjunctiva
a transparent protective covering over the exposed part of the eye. the conjunctiva is a thin mucous membrane folded like and envelope between the eyelids and eyeball
lacrimal apparatus
provides constant irrigation to keep the conjunctiva and cornea moist and lubricated. The lacrimal gland is located in the upper outer corner of each eye, it secretes tears
Explain how the eyes move together
their axes always parallel. this is important because the brain can tolerate seeing only one image.
What cranial nerves are related to the extraocular muscles.
III, IV, VI
sclera
a tough protective white covering
cornea
very sensitive to touch
choroid
has dark pigmentation to prevent light from reflecting internally and is heavily vascularized to deliver blood to the retina
anterior chamber
posterior to the cornea and in front of the iris and lens, contains clear watery fluid
posterior chamber
lies behind the iris to the sides of the lens, contain clear watery fluid
The image formed on the retina is…
upside down and reversed from its actual appearance in the outside world
optic chiasm
where optic nerves from each eye cross over. this the right side of the brain looks at the left side of the world
What is the pupillary light reflex?
normal constriction of the pupils when bright lights shines on the retina
-involves cranial nerve II (sensory) and cranial nerve III(motor)
what is a consensual light reflex?
when the other eye that isn’t exposed to a bright light constricts because the other eye did
Pupillary light reflex with someone who is blind
- stimulation of the normal eye produces both a direct and a consensual light reflex
- stimulation of the blind eye causes no response because the sensory afferent in cranial nerve II is destroyed
what is fixation?
a reflex direction of the eye toward an object attracting a person’s attention. the image is fixed in the center of the visual field, the fovea centralis
What is accommodation?
the adaptation of the eye for near vision
Vision in infants/Children
- peripheral vision is intact in the newborn infant
- the macula, area of keenest vision, is absent at birth but developing by 4 months and mature by 8 months
- at birth the iris shows little pigmentation
- lens in nearly spherical at birth, growing flatter throughout life
changes around the eye the aging adult experiences
- skin loses its elasticity, causing wrinkling and drooping
- fat tissues and muscles atrophy
What happens to the lacrimal glands of the aging adult?
they involute causing decreased tear production
Why does the aging adult get floaters?
-inside the globe, floaters appear in the vitreous as a result of debris that accumulates because the vitreous is not renewed as continuously as the aqueous humor
why is near vision commonly affected in the aging adult?
decreased power of accommodation in the lens (called presbyopia)
In older adults the most common causes of decreased visual functioning are…?
- cataract formation- lens opacity
- glaucoma- increased intraocular pressure
- macular degeneration- breakdown of cells in the macula of the retina, loss of central vision
What is significant about individuals with light iris colors and vision?
- dark irides have darker retinas
- individuals with light retinas generally have better nightv vision but can have pain in an environment that has too much light
What is the leading cause of age related blindness in whites?
macular degenerations
what is the leading cause of age related blindness in blacks?
glaucoma and cataracts
How does vision work?
light rays from a viewed object enters the cornea and are refracted on to the macula. the stimulus is then inverted, reversed, and focused on the retina which sends the stimulus through the visual pathway to the brain where the image returns to its original form
what eye problems do pregnant women experience?
blurry vision, dry eyes, thickened cornea, visual field changes