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
What requires an acute assessment of the eyes?
anything that requires immediate medical attention like trauma, foreign body etc
What is strabismus?
cross eyed, a deviation in the axis of the eye
Additional history for the aging adult
- problems with night vision
- when was the last time you were tested for glaucoma
- history of cataracts
- do your eyes feel dry
- any decrease in usual activities such as reading or sewing?
Snellen Eye Chart
- accurate measure of visual acuity
- it has lines of letters arranged in decreasing size
- position the patient 20 ft from the chart
- test eyes separately with an opaque card/eye cover and then together
- leave glasses/contacts in
- ask patient to read through the chart to the smallest line of letters possible
- note hesitancy, squiting, leaning forward, misreading letters
explain what 20/30 vision means
you can read at 20 feet what the normal eye can see at 30 feet
What test is used to test near vision?
- similar to the snellen eye chart; Jaeger Card
- hold card 14 inches from eye
- if a screening card isn’t available ask the patient to read from a newspaper or magazine
presbyopia
the decrease in power of accommodation with aging
What is a confrontation test?
- gross measure of peripheral vision
- position yourself 2ft away from patient at eye level
- cover opposite eye as patient
- bunny rabbit fingers inward
- should be seen the same time you see
- with the temporal visual field start slightly behind the person
- normal results: 50 degrees upward, 90 degrees temporally, 70 degrees down, and 60 degrees nasally
What is the Hirschberg test?
- corneal light reflex
- assess the parallel alignment of the eye axes by shining a light toward the person’s eyes. direct the person to stare straight ahead as you hold the light about 12 inches away. note the reflection of the light on the corneas. should be exactly the same
What is the Cover Test?
- detects small degrees of deviated alignment by interrupting the fusion reflex that normally keeps two eyes parallel
- if muscle weakness exists, the covered eye will drift into a relaxed position
What does the six cardinal positions of gaze test for?
- muscle weakness
- progress clockwise
- nystagmus
what is nystagmus?
a fine, oscilltating movement best seen around the iris
what is lid lag and what does it usually occur with?
- if you see a white rim of the sclera between the lid and the iris during the siz cardinal positions of gaze test
- occurs with hyperthyroidism
what might you see while inspecting the external ocular structures of African americans?
- slight protrusion of the eyeball beyond the supraorbital ridge, called exophthalmos
- may have a gray-blue or muddy color to the sclera
what is scleral icterus?
an even yellowing of the sclera extending up to the cornea, indication jaundice
How do you check the lacrimal apparatus?
-presence of excessive tearing may indicate a blockage of the nasolacrimal duct. check this by pressing the index finger against the sac, just inside the lower orbital rim, not against the side of the nose, pressure will slightly evert the lower lid, but there should be no other response to the pressure
how do you check the cornea and lens?
shine a light from the side across the cornea, check for smoothness and clarity.
how do you assess the iris and pupil?
- the iris normally appears flat, with a round regular shape and even coloration. note the size, shape, and equality of the pupils. normally pupils appear round, regular and equal in size in both eyes
- test the pupillary light reflex in a darken room while asking the person to gaze straight ahead. bring in light from the side and watch the pupils constrict.
What is anisocoria?
the term used for the small percentage of people (5%) who normally have pupils of two different sizes
What is ptosis?
drooping eye brows
How do you test for accommodation?
by asking the person to focus on a distant object. this dilates the pupils. then have the person shift the gaze to a near object, such as your finger held about 3 inches from the person’s nose.
-a normal response includes 1) pupillary constriction
and 2)convergence of the axes of the eyes
what does PERRLA stand for?
Pupils Equal Round React to Light and Accommodation
what is the ocular fundus?
the internal surface of the retina, inspected with an ophthalmoscope
When using an ophthalmoscope what should you do?
- remove glasses from yourself and patient, contact lenses can stay in
- match sides with person to avoid bumping noses
what is the red reflex?
- normal, the red glow filling the persons pupil
- caused by the reflection of your ophthalmoscope light off the inner retina
how do you test light perception in infants?
- using the blink reflex, the neonate responds to bright light
- you can normally test the pupillary light reflex
- you cannot infer that the infant can see
Eye sight development from birth to 10 months
birth to 2 weeks : refusal to reopen eyes after exposure to bright light; increasing alertness to object; infant may fixate on an object
By 2 to 4 weeks: infant can fixate on an object
By 1 month: infant can fixate and follow a light or bright toy
By 3 to 4 months: infant can fixate, follow and reach for the toy
By 6 to 10 months: infant can fixate and follow the toy in all directions
What test do you use to screen children ages 2.5 years to 2 years 11 months?
-Alien test (picture cards)
how do you test for color blindness?
-Ishihara’s test- a series of polychromatic cards. ask to say the number they see
What kind of disorder is color blindness?
recessive X-linked trait, mainly affects males
What is pseudostabismus?
while they are present, epicanthal folds give a false appearance of malalignment
-commonly seen in Asians and many infants (later go away)
By what age is the permanent eye color differentiated in babies?
6 to 9 months
What are pingueculae?
- seen in aging adult
- yellowish, elevated nodules on the sclera, due to thickening of the bulbar conjunctiva from prolonged exposure to sun, wind, and dust
What is arcus senilis?
- seen in aging adult
- around the cornea commonly
- gray white arc or circle around the limbus, is due to deposition of lipid material
- as more lipid accumulates, the cornea may look thickened and raised, but the arcus has no effect on vision
what is Xanthelasma?
soft, raised yellow plaques occurring on the lids at the inner canthus
- 5th decade of life
- no pathologic significance
Esotropia
inward turning of the eye (strabismus)
exotropia
outward turning of the eye(strabismus)
phoria
mild weakness, apparent only with the cover test and less likely to cause amblyopia than a tropia but still possible
esophoria
nasal (inward) drift
exophoria
temporal (outward) drift
Ptosis
drooping upper lid
Hordeolum
stye
mydriasis
dilated and fixed pupils
-drugs, acute glaucoma, central nervous system injury, circulatory arrest, deep anesthesia
Argyll Robertson pupil
no reaction to light
-central nervous system syphilis, brain tumor, meningitis, chronic alcoholism
Horner’s syndrome and eyes
- unilateral small regular pupil,
- occurs with horners syndrome a lesion of the sympathetic nerve
Miosis
- constricted fixed pupils
- brain damage of the pons, drugs, iritis, narcotics
Adie’s pupils (Tonic pupil)
sluggish reaction to light and accommodation
-usually unilateral, no pathological significance
Cranial Nerve III damage
-unilateral dilated pupil with no reaction to light or accommodation. may also have ptosis with eye deviating down and laterally
