objective 9 Flashcards
protect the eye from injury.
eyelids
larger and more mobile
upper eyelids
filter out dust and dirt
eyelashes
elliptical open space between the eyelids
palpebral fissure
the eyelids margins approximate completely
when the eyes are closed
the upper eyelid covers part of the iris. the lower eyelid margin is just at the limbus
when the eyes are open
boarder between the cornea and sclera
limbus
the corner of the eye, angle where the eyelids meet
canthus
a small fleshy mass that contains sebaceous glands
caruncle
strips of connective tissue that give the eyelid shape. they are located in the upper eyelid
tarsal plates
contained in the tarsal plates, they secrete an oily lubricating material onto eyelids
meibomian glands
transparent protective covering on the exposed part of the eye
conjunctiva
provides constant irrigation to keep the conjunctiva and cornea moist and lubricated
lacrimal apparatus
where the tears drain into
puncta
how many eye muscles are there?
6
tough protective white covering that is continuous anteriorly with the cornera
outer fibrous sclera
transparent and covers iris and pupil
cornea
has dark pigmentation to prevent light from reflecting
internally and is heavily vascularized to deliver blood to the retina
choroid
controls the amount of light admitted into the retina
iris
size determined by a balance of the parasympathetic and sympathetic chains of the autonomic nervous system
pupil
serves as a refracting medium, keeps a viewed object in constant focus on retina
lens
contains fluid that continuously flows
anterior chamber and posterior chambers
visual receptor of the eye which light waves are changed into nerve impulses
retina
area in which fibers from the retina converge to form the optic nerve
optic disc
include paired artery and vein extending to each quadrant
retinal vessels
recieves and transduces light from the center of the visual field
macula
area of sharpest and keenest vision
fovea centralis
Light rays are refracted through the
cornea, aqueous humor, lens, and vitreous body, the light rays strike
the retina
* Retina transforms light stimulus to nerve impulses
* Nerve impulses are conducted via the optic nerve and the optic tract
to the visual cortex of the occipital lobe
visual pathways and fields
normal constriction of the pupils
when a bright light shines on the retina
pupillary light reflex
when one eye is exposed to bright light, constriction of that pupil occurs
direct light reflex
when one eye is exposed to bright light, the other pupil constricts at the same time
consensual light reflex
reflex direction of the eye toward an object attracting a persons attention
fixation
adaptation of the eye for near vision
accomodation
what are the eyes like at birth?
Eye function limited, matures fully during early years (Eyeball
reaches adult size by 8 years)
* Peripheral vision intact
* Poorly coordinated eye movements (binocularity by 3-4
months)
* Macula absent (begins developing by 4 months and is mature
at 8 months)
* Iris has little pigmentation, the pupils are small, the lens is
nearly spherical
* Most neonates born farsighted (80%)
Difficult to perform on an infant - only check the red reflex
* Young children and school-age children - examination same as
for adults
* When testing visual acuity, screening method chosen
depends on the age of the child (p. 333 - 334)
* Testing for strabismus is an important screening
measure during early childhood
funduscopic examination
no effect on vision
arcus senilis
what are the most common causes of decreased visual functioning?
Macular degeneration
* Cataract formation
* Glaucoma – Chronic open-angle glaucoma is the most
common type
apparent but not true dropping of the eyelid
pseudoptosis
a yellowish, raised growth on the conjunctiva
pingueculae
skin fold of the upper eyelid covering the inner corner of the eye
epicanthal folds
how do we prep for eye examanation?
Position the client
* Standing for vision screening
* Sitting up with the head at the examiner’s eye level for the
remainder of the examination
what equipment do we use for eye examination?
Snellen Chart
* Handheld vision screener
* Opaque card
* Penlight
* Applicator stick
* Ophthalmoscope
Most commonly used
* An accurate measure of visual acuity
* Contains lines of letters in decreasing size
* When testing the client’s vision:
* Ensure that there is good lighting
* Place the chart at eye level and position client exactly 20 feet from
the chart
* Ask the client to shield one eye with an opaque card
* Ask client to read through the chart to the smallest line of letters
that can be seen
* Encourage the client to try and read the next smallest line as well
* Test each eye separately
snellen eye chart
Gross measure of peripheral vision
* When testing the client’s vision:
* The examiner is positioned at eye level with client,
approximately 60 cm away
* The client covers one eye with opaque card and looks
straight at examiner with the other
* The examiner covers their own eye opposite of the one
covered by the client
* The uncovered eye is the one being tested
confrontation test
This test assesses parallel alignment of the eyes.
* Ask the client to look straight ahead.
* Hold a light about 30 cm away from the client and shine
it toward the client’s eyes
corneal light reflex test
what is normal for corneal light reflex?
Symmetry of the light reflex. The reflection of the
light on the corneas (bright white dots) should be in exactly
the same spot on each eye, as shown below
what is abnormal for corneal light reflex?
Asymmetry of the light reflex. The
reflection of the light on the corneas will not be
in the same spot. This indicates a deviation in
alignment (i.e. due to eye muscle weakness or
paralysis)
Perform Cover-Uncover Test on Both Eyes:
* This test detects small degrees of deviated alignment
* Ask the client to stare straight ahead at the nose of the examiner
* Cover one eye with an opaque card
* Observe the uncovered eye – the examiner should see a steady fixed gaze,
this is a normal response
* Uncover the covered eye and observe it for movement
* If there is muscle weakness, the covered eye will drift into a relaxed
position
cover-uncover test
what is the normal findings for cover-uncover test?
eye is staring straight ahead
what is the abnormal findings for cover-uncover test?
the eye jumps to establish fixation. This indicates that
muscle weakness exists in that eye
This test leads the eyes through the 6 cardinal positions of gaze
* Muscle weakness will be evident during movement
* Instruct the client to hold their head steady and to follow the
movement of your finger only with their eyes
* Hold the finger back about 30 cm from the client’s face
* Move the finger to the first cardinal position and hold it there for
a moment then return back to center
* Progress clockwise through all the cardinal positions
diagnostic’s position test
what are the normal findings for disgnostics postion test?
parallel tracking of the finger with both eyes
what are the abnormal findings for disgnostics postion test?
eye movement is not parallel
Mild nystagmus at the extreme lateral gaze is normal
* Nystagmus at any other position is abnormal
assess for nystagmus
Observe whether the upper eye lid continues to overlap the
superior part of the iris
* Normal: It should overlap even during downward
movement
* Abnormal: Lid lag - a white rim of sclera is observed
between the iris and the eyelid
assess for lid lag
what are normal findings for eyebrows?
Bilateral, symmetrical movement as facial expression
changes, no scaling or lesions
what are abnormal findings for eyebrows?
Asymmetrical or absent movement, scaling,
absence of parts of the eyebrow
what are normal findings for eyelids?
Upper eyelids normally overlap superior part of the iris
* When eyes are closed, the upper and lower eyelids approximate
completely
* Skin is intact with no redness, swelling, discharge or lesions
* Palpebral fissures are horizontal (slightly upward in some people of East
Asian descent)
what are abnormal findings for eyelids?
Lid lag, incomplete closure, periorbital edema, ptosis
* Ectropion and entropion
what are the normal findings for eyeballs?
Aligned, no protrusions or sunken appearance
what are abnormal findings for eyeballs?
Protruding eyes (exophthalmos), sunken eyes
(enophthalmos)
how do you assess the conjunctiva and sclera?
Ask client to look up
* Use your (the examiner) thumbs to slide the client’s lower eyelids down
along the orbital rim.
* Inspect the exposed area
what are the normal findings for the conjunctiva and sclera?
Eyeballs – moist and glossy
* Conjunctiva – clear, show the normal colour of the structures below
* Sclera – china white
how do you assess the lacrimal apparatus?
Ask client to look down
* Use your (examiner) thumbs and slide the outer part of the
upper eyelid up along the bony orbit
* Doing this will expose the area under the eyelid
* Inspect for redness or swelling
how do you assess the nasolacrimal duct for blockage?
The examiner presses the index finger against the
sac just inside the orbital rim (not against the side of the
nose), there will be absence of drainage
what are the normal findings for nasolacrimal duct?
The pressure will cause the lower eyelid to slightly
evert. No other response should be observed.
what are the abnormal findings for the nasolacrimal duct?
Red, swollen, and tender puncta; regurgitation
of fluid from the puncta when assessed (indicates
blockage)
how do you assess the cornea and lens>
From the side, shine a light across the client’s cornea – this
will highlight any abnormalities in the corneal surface
* Assess for smoothness and clarity
what are the abnormal findings for the cornea and lens?
corneal abrasions
* Opacities in the cornea, anterior chamber, or the lens
behind the pupil
* Careful, do not confuse with arcus senilis in the older
adult
irregular ridges in reflected light, produces a shattered appearance with light rays
corneal abrasions
what are the normal findings for the iris?
appears flat, round, regular shape, and even colouration
what are the abnormal findings for the iris?
irregular shape
what are the normal findings for the pupil?
round, regular, equal bilaterally, resting size from 3-5mm
how do we assess pupillary light reflex?
Darken the room and ask the client to gaze into
the distance (this promotes pupil dilation)
* Advance a light from the side and note the
response
what are the normal findings for pupillary light reflex?
direct light reflex, consensual light reflex
what are the abnormal findings for pupillary light reflex?
Dilated pupils, dilated and fixed pupils,
constricted pupils, sluggish pupils, unequal or no response to
light
how do we assess accomodation?
Instruct the client to focus on a distant object (to help dilate
the pupils)
* Ask the client shift gaze to a near object located 7-8 cm away
from the nose
what are the normal findings for accomodation?
Pupillary constriction, convergence of the
eyes
what are the abnormal findings for accomodation?
Absence of constriction or convergence,
asymmetrical response
enlarges the view of the eye and allows for inspection of the media and ocular fundus
ophthalmoscope
anterior chamber, lends, vitreous
media
internal surface of the retina
ocular fundus
unit strength of each lens
dioptre
how do we use a opthalmoscope?
darken the room
remove the clients glasses
use the large white aperture with the white light
ask the client to keep looking at a fixed point on the wall across the room
match sides with the client
place free hand on clients shoulder to help orientate the examiner in space
can use thumb to anchor clients upper eyelid
Start the examination about 25 cm away from the client at an
angle of approximately 15 degrees lateral to the client’s line of
vision
* Find the red reflex - once
located, keep sight of it and move closer to the eye
* If you lose the red reflex, adjust the angle and find it again
nearsighted
myopia
farsighted
hyperopia
Grey-white new moon shape
* Present when pigmentation is absent in the choroid
layer
* Can be seen by looking directly at the sclera
scleral crescent
Black in colour
* Caused by accumulation of pigment in the choroid
pigment crescent
Colour normally ranges from light red to dark brown-red
* The colour usually corresponds to the client’s skin colou
fundua
Size and Location:
* Size - 1 DD in size
* Location - 2 DD temporal to the disc
macula
