Download Chapter 7 Body Systems

Eyes
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1. Discuss the anatomy and physiology of the
eye.
2. Conduct a history related to the eye.
3. Discuss examination techniques for the
eye.
4. Identify normal age and condition
variations of the eye in an older adult.
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5. Describe the following deviations from
expected findings: exophthalmos,
strabismus, periorbital edema, ptosis,
conjunctivitis, iritis, glaucoma, corneal
abrasion, and cataract.
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. an imprint of Elsevier Inc.
Copyright © 2015 by Mosby,
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Transmits visual stimuli to the brain
for interpretation
Occupies orbital cavity/anterior aspect
exposed
Direct embryologic extension of the brain
Attached by four rectus muscles/two oblique
muscles
Innervated by cranial nerves III, IV, and VI
Connected to brain by cranial nerve II
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Far Point = 20 feet  relaxed eye: with lens at rest
(taut), normal vision at 20 ft & beyond (20/20 vision)
Emmetropic eye (normal)
Focal
plane
Focal point is on retina.
To achieve near vision, light must be ‘more bent’. This requires
3 simultaneous processes to achieve focus: accomodation of
the lens (thickness), pupil constriction & convergence.
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Composed of five structures
 Eyelid
 Conjunctiva
 Lacrimal gland
 Eye muscles
 Bony skull orbit
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Eyelids
 Distribute tears over eye surface
 Limit amount of light entering the eye
 Protect the eye from foreign bodies
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Conjunctiva
 Protects the eye from foreign bodies and
desiccation
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Lacrimal gland
 Produces tears that moisten the eye
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Figure 11-03. Important Landmarks of the Left External Eye. (From Thompson et al, 1997.)
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Eye muscles
 Each eye is moved by six muscles.
▪ Superior, inferior, medial, and lateral rectus muscles
▪ Superior and inferior oblique muscles
 They are innervated by cranial nerves III
(oculomotor), IV (trochlear), and VI (abducens).
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superior oblique
muscle
superior oblique
tendon
superior rectus
muscle
lateral rectus
muscle
inferior rectus
muscle
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inferior oblique
muscle
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Composed of three layers
 Outer fibrous layer
▪ Sclera posteriorly and cornea anteriorly
 Middle layer
▪ Choroid posteriorly and ciliary body/iris anteriorly
 Inner layer
▪ Retina
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choroid
retina
sclera
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Five major structures
 Sclera
 Cornea
 Iris
 Lens
 Retina
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Sclera
 White of the eye
 Avascular
 Supports internal eye structures
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Cornea
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Continuous with the sclera anteriorly
Clear
Sensory innervation for pain
Major part of the refractive power of the eye
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 The iris is a circular, contractile muscular disc
containing pigment cells that produce the color of
the eye.
▪ Dilates/contracts to control amount of light traveling
through the pupil to the retina
 The ciliary body produces the aqueous humor and
contains the muscles controlling accommodation.
 The choroid is a pigmented, richly vascular layer
that supplies oxygen to the outer layer of the
retina.
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Lens
 A biconvex, transparent structure located
immediately behind the iris
 Changes in lens thickness allow images from
varied distances to be focused on retina
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Retina
 Sensory network of the eye
 Transforms light impulses into electrical impulses,
which are transmitted through:
▪
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Optic nerve
Optic tract
Optic radiation
Visual cortex
Consciousness in the cerebral cortex
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Retina
 Cortex interprets impulses as visual objects.
 Major landmarks of the retina include:
▪ Optic disc, from which the optic nerve originates,
together with the central retinal artery and vein
▪ Macula, or fovea, is site of central vision
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Figure 11-04. The Optic Chiasm. (Modified from Thompson et al, 1997.)
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The major physiologic eye change that occurs
with aging is a progressive weakening of
accommodation (focusing power) known as
presbyopia
Loss of lens clarity and cataract formation
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Vision difficulty: decrease acuity, blurring,
blind spots.
Pain
Strabismus, diplopia
Redness, swelling
Watering, discharge
History of ocular problems
Glaucoma
Use of glasses or contact lenses
Self-Care behaviors
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Any difficulty seeing or any blurring? Blind
spots?
Constant, or does it come and go?
Do objects appear out of focus or clouding of
objects/
Do spots move in front of your eyes?
Any halos, rainbows, rings around objects?
Any blind spot? Any loss of peripheral vision?
Any night blindness?
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Any eye pain?
Come on suddenly?
Quality: burning or itching? Or sharp, pain
with bright light?
A foreign body sensation? Or deep aching? Or
headache in brow area?
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Strabismus, diplopia: Any history of crossed
eyes? Does this occur with eye fatigue
 Ever see double? Constant, or does it come and
go? In one eye or both?
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Redness, Swelling
 Any redness or swelling in eyes?
 Any infections? Now or in past/ When do these
occur? In a particular time of year?
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Watering, discharge
 Any watering or excessive tearing?
 Any discharge? Any matter in the eyes? Is is hard
to open your eyes in the morning/ What color is
the discharge?
 How do you remove matter from eyes?
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Past history of ocular problems
 Any history of injury or surgery to eye? Any
history of allergies?
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Glaucoma
 Have you ever been tested for glaucoma? What
were the results?
 Do you have any family history of glaucoma?
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Use of glasses or contact lenses
 Do you wear glasses or contact lenses? How do
they work for you?
 Last time your prescription was checked?
 If you wear contacts, are there any problems?
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How do you care for contacts? How long do
you wear them? How do you clean them? Do
you remove them for certain activities?
Last vision test? Ever tested for color?
Any environmental conditions at home or at
work that may affect your eyes?
What medications are you taking?
If you have experienced a vision loss, how do
you cope?
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Have you noticed any visual difficulty with
climbing stairs or driving? Any problem with
night vision?
When was last time tested for glaucoma?
Is there a history of cataracts? Any loss or
progressive blurring of vision?
Do your eyes ever feel dry or burning? What
do you do for this?
Any decrease in usual activities?
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. an imprint of Elsevier Inc.
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Snellen eye chart
Rosenbaum/Jaeger near vision card
Penlight
Ophthalmoscope
Eye cover, gauze, or opaque card
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Test for:
 Central vision
 Near vision
 Peripheral vision
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Use Snellen chart.
It has lines arranged in decreasing size
Place chart 20 feet from person
If person wears glasses or contact lenses
leave them on.
Ask person to read through chart ot
smallest line of letter possible: encourage
trying next smallest line also.
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Typically, an eyeball that's
too long causes myopia. But
an abnormally shaped
cornea or lens can also be to
blame.
Light rays focus just in front
of the retina, instead of
directly on it.
Nearsightedness often
develops in school-age
children and teens, who need
to change glasses or
contacts frequently as they
grow. It usually stabilizes
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by the early 20s.
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Near vision
 Use Rosenbaum pocket screener
 Each eye tested individually
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Color vision
 Rarely tested in the routine physical examination
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Presbyopia: as we age, the lens
becomes stiff and will not accommodate
to allow bending of light for near vision…
we become “farsighted”.
Slide 41
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Color blindness is
an inherited condition.
In most cases of
color blindness, the
green-sensitive
pigment is missing
or deficient. In
others red may be
deficient.
Less vibrant color
is perceived and
the ability to
distinguish
between colors is
lost.
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Peripheral vision
 Estimate with confrontation test.
 Position yourself at eye level with person about 2
feet away.
 Direct person to cover one eye with an opaque
card and cover your own eye opposite to person’s
covered one.
 Hold pencil as target midline between you and
person and slowly advance it in from periphery/
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Figure 11-05. Evaluation of Peripheral Fields of Vision. A, Temporal field. B, Nasal field.
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Examination performed in systematic
manner beginning with appendages and
moving inward
Techniques
 Inspection
 Palpation
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Surrounding structures
 Inspect eyebrows for size, extension, and hair
texture.
 Inspect orbital area for edema, puffiness, and
sagging tissue below orbit.
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Eyelid inspection
 Inspect closed lid for fasciculations and tremors.
 Check ability to close completely/open widely.
 Observe margin for flakiness, redness, and
swelling.
 Look for eyelashes.
 Note eye opening.
▪ Ptosis
 Note any eversion or inversion of lids.
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Eyelid palpation
 Palpate for nodules.
 Palpate the eye itself through closed lids.
▪ Digital palpation tonometry
▪ Pain
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Conjunctivae inspection
 Usually inapparent, clear, and free of erythema
 Inspect lower portion by pulling down lower lid
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Figure 11-12. Pulling Lower Eyelid Down to Inspect the Conjunctiva.
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Conjunctivae inspection (Cont.)
 Upper lid is inspected only if foreign body is in
the eye.
 Look for redness/exudate.
 Look for pterygium.
▪ Abnormal growth of conjunctiva that extends over the
cornea from the limbus
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Figure 11-08. Ectropion. (From Stein et al, 1988.)
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Cornea
 Examine clarity of the cornea by shining light on
it.
▪ Cornea is normally avascular; blood vessels should not
be present.
 Inspect for corneal arcus (arcus senilis).
▪ Composed of lipids deposited in the periphery of the
cornea
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Corneal Abrasion
slit lamp
exam
flouriscene drops
& black light
exam
Slide 54
Foreign Body of the
Eye Surface
Many nerve endings lie just
beneath the surface of your
cornea, so a tiny speck can
be surprisingly painful.
If gentle flushing with lukewarm
water doesn't dislodge the FB,
a medical provider can remove
the object & provide antibiotic
drops to protect the cornea
from infection.
Metallic chips may cause a
‘rust ring’.
Slide 55
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Iris and pupil
 Inspect iris for pattern, color, and shape.
 Test for direct/consensual light response.
 Test pupils for accommodation.
▪ The pupils should constrict when the eyes focus on the
near object.
 Estimate pupil size and compare for equality.
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Lens
 Inspect for transparency/clarity.
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Sclera
 Examine to ensure that it is white.
 Inspect for senile hyaline plaque.
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Lacrimal apparatus
 Inspect lacrimal gland.
 Palpate lower orbital rim near inner canthus.
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Test eye movements using six cardinal fields
of gaze.
 Check for nystagmus.
 Note lid lag.
 Note exposure of sclera above iris.
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Figure 11-22. Cranial Nerves and Extraocular Muscles Associated with the Six Cardinal Fields of Gaze.
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Use corneal light reflex to test extraocular
muscle balance.
 If imbalanced, perform cover-uncover test.
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Figure 11-23. Evaluating Eye Fixation by the Cover-Uncover Test. A, Patient focuses on near object. B,
Examiner evaluates movement of covered eye as cover is removed.
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Inspection of interior eye with
ophthalmoscope permits visualization of:
 Optic disc
 Arteries
 Veins
 Retina
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Visualize red reflex.
 Opacities appear as black densities.
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Examine
 Fundus
 Vascular supply
 Disc margins
 Macula
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Look for unexpected findings such as:
 Myelinated nerve fibers
 Papilledema
 Glaucomatous cupping
 Drusen bodies
 Cotton wool bodies
 Hemorrhages
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Figure 11-29. Method of Describing the Position and Dimension of a Lesion in Terms of Disc Diameter.
The lesion in this illustration is described as being 2 disc diameters (DD) from the optic disc at the 2 o'clock
position. The lesion is DD long and DD wide.
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Visual Acuity
 Central acuity may decrease, particularly after 70
years of age; peripheral vision may be diminished.
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Ocular structures
 Eyebrows may show loss of outer one third to one
half of hair.
 Skin around eyes may show wrinkles
 Eyes may appear sunken
 Lacrimal apparatus may decrease tear production
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Cornea may look cloudy.
Pupillary light reflex may be slowed
Lens loses transparency and looks opaque
Retinal structures generally have less shine.
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Exophthalmos
Strabismus
Periorbital edema
Ptosis
Conjunctivitis
Iritis
Acute glaucoma
Corneal abrasion
Cataract
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Figure 11-38. Thyroid Exophthalmos. See also Figure 10-11. (From Stein et al, 1994.)
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Cataracts
In good health, the lens focuses
light into a sharp, clear image
on the retina, which captures
the image like film in a camera.
As we age, protein builds up in
the lens, clouding it, & defocusing light sent to the retina.
By the time we're 80 years old,
more than half of us will
have a cataract.
Diabetes, smoking, or prolonged
sunlight exposure may increase
the risk. Surgery that replaces
the clouded lens with an artificial
lens is highly effective.
Figure 11-43. A, Snowflake cataract of diabetes. B, Senile cataract. (From Donaldson, 1976.)
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Glaucoma
You can't feel it, but deterioration of the optic nerve due to
elevated eye pressure can silently steal your sight, a condition
called glaucoma. Gradual loss of peripheral vision may
progress to central visual loss and blindness.
Those at higher risk include:African-Americans over 40, anyone
over 60 (esp Mexican-Americans) & people with a family history.
Glaucoma can be treated with meds or surgery. Regular eye
exams every 1-2 years after age 40 can catch it early.