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Chapter 34 • Vaginal Discharge and Itching 421
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DIFFERENTIAL DIAGNOSIS OF Common Causes of Vaginal Discharge and Itching
CONDITION HISTORY PHYSICAL FINDINGS DIAGNOSTIC STUDIES
Discharges
Physiological
discharge
Bacterial
vaginosis
Candida
vulvovaginitis
Trichomoniasis Watery discharge; foul odor Profuse, frothy, greenish
Atrophic
vaginitis
Allergic
vaginitis
Foreign body Red and swollen vulva; vaginal
Chlamydia Partner with nongonococcal
Gonorrhea Partner with STI; often
Pelvic
inflammatory
disease (PID)
Itching and Lesions
Syphilis History of painless ulcerative
Genital warts Mild-to-moderate itching, foul
Herpes History of prodromal syndrome,
Molluscum
contagiosum
CMT, cervical motion tenderness; HPF, high-power field; KOH, potassium hydroxide; NAAT, nucleic acid amplification test; WBC, white blood cell.
Increase in discharge; no foul
odor, itching, or edema
Foul-smelling discharge Homogeneous thin white or gray
Pruritic discharge White, curdy discharge; pH 4.0-5.0 KOH prep: mycelia,
Dyspareunia; vaginal dryness Pale, thin vaginal mucosa;
New bubble bath, soap, douche,
for example
discharge; history of use of
tampon, condom, or diaphragm
urethritis; asymptomatic
asymptomatic
Bleeding, abdominal pain, fever,
and vaginal discharge; increasing
amount of vaginal discharge and
bleeding after intercourse
lesion; rash on palms and soles
of feet; warty growth on vagina
or anus
vaginal discharge; child: history
of sexual abuse; adult: new or
multiple partners; history of warts
paresthesias, burning, itching;
may have mucoid vaginal
discharge
History of contact with infected
person; if inflamed: itching
Clear or mucoid; pH ,4.5 Up to 3-5 WBCs/HPF;
epithelial cells,
lactobacilli
Presence of KOH “whiff”
discharge; pH .4.5
discharge; red friable cervix;
pH 5.0-6.0
pH .4.5
Foul smell, erythema; “lost
tampon”; pH ,4.5
Bloody, foul-smelling discharge WBCs
May or may not have purulent
discharge
Purulent discharge; inflammation
of Skene/Bartholin glands
CMT and adnexal tenderness; may
also have guarding and rebound
tenderness
Chancre: usually 1 but can be
more, painless ulceration;
condylomata lata: flat, whitish
papule or plaque; maculopapular
rash: palm, soles, body
Moist, pale-pink, verrucous
projections on base; located on
vulva, vagina, cervix, or perianal
area
Grouped vesicles on red base,
erode to an ulcer; if on mucous
membrane, exudates form; if
on skin, crusts form; redness,
edema, tender inguinal lymph
nodes
Flesh-colored, dome-shaped
papules, some with umbilication;
usually 2-5 mm in diameter
test; presence of clue
cells; few lactobacilli
(see Figure 34-1)
budding, branching
yeast, pseudohyphae
(see Figure 34-1)
Round or pear-shaped
protozoa; motile
“gyrating” flagella (see
Figure 34-1)
Folded, clumped
epithelial cells
WBCs
DNA probe; NAATs; .10
WBCs/HPF
Gram stain; culture;
DNA probe; NAATs
WBC; culture; DNA
probe; NAATs; Gram
stain
Serology for syphilis
Acetic acid test: white
Viral culture; Tzanck
smear
None
422 Chapter 34 • Vaginal Discharge and Itching
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REFERENCES AND READINGS
Anderson MR, Klink K, Cohrssen A: Evaluation of vaginal com-
plaints, JAMA 291:1368, 2004.
Bachmann GA, Nevadunsky NS: Diagnosis and treatment of atro-
phic vaginitis, Am Fam Physician 61:3090, 2000.
Burstein G, Murray P: Diagnosis and management of sexually trans-
mitted diseases among adolescents, Pediatr Rev 24:19, 2003.
Centers for Disease Control and Prevention, Workowski KA,
Berman SM: Diseases characterized by urethritis and cervicitis. Sexually transmitted diseases treatment guidelines 2006
[published errata appear in MMWR Morb Mortal Wkly Rep 2006
Sep 15;55:997]. MMWR Morb Mortal Wkly Rep 55:35, 2006.
Coco AS, Vandenbosche M: Infectious vaginitis: an accurate diagnosis
is essential and attainable, Postgrad Med 107:63, 2000.
Eckert LO: Clinical practice. Acute vulvovaginitis, N Engl J Med
355:1244, 2006.
Egan ME, Lipsky MS: Diagnosis of vaginitis, Am Fam Physician
62:3090, 2000.
French L, Horton J, Matousek M: Abnormal vaginal discharge: using
ofce diagnostic testing more effectively, J Fam Pract 53:805,
2004.
Jasper J: Vulvovaginitis in the prepubertal child, Clin Ped Emerg
Med 10:10, 2009.
Mitchell H: ABC of sexually transmitted infections: vaginal discharge—
causes, diagnosis, and treatment, BMJ 328:1306, 2004.
Nyirjesy P: Chronic vulvovaginal candidiasis, Am Fam Physician
63:697, 2001.
Owen MK, Timothy L, Clenney TL: Management of vaginitis, Am
Fam Physician 70:2125, 2004.
Parks D, Yetman R: Diagnosis and management of pelvic inam-
matory disease in adolescents, J Pediatr Health Care 17:145,
2003.
Teran S, Walsh C, Irwin KL: Chlamydia trachomatis infection in
women: bad news, good news, and next steps in prevention, J Am
Med Womens Assoc 56:100, 2001.
C H A P T E R
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35
Vision Loss
ision loss is a condition that ranges from visual
impairment to total blindness. For vision to
V
photoreceptors in the retina that collect light and send
neural impulses to the brain. These impulses are then
processed to give information on what is being seen.
Vision loss occurs with any interruption in this visual
pathway, such as opacication of the cornea, lens, or
vitreous body (see Figure 27-1 for the anatomical
structures of the eye). Vision loss also occurs when
light energy cannot be converted into neural impulses,
such as in glaucoma, retinal detachment, ischemic
optic nerve atrophy, and pituitary or occipital tumors.
Because vision loss is a self-reported condition, functional causes, formerly called malingering or hysteria,
can be considered.
are cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy. In all cases, impaired
vision requires evaluation by an ophthalmologist.
However, knowledge of the causes of vision loss can
provide important clues to the diagnosis of these
conditions.
DIAGNOSTIC REASONING:
FOCUSED HISTORY
occur, light is transmitted through the eye to
The most common causes of vision loss in adults
Blurring of Vision
Distinguish between loss of vision and loss of visual
acuity. Vision loss is the absence of vision, completely
or partially, in one or both eyes. Blurriness refers to a
change in the acuity of vision. The most common
cause of visual acuity change is refractive error.
Ability to Focus
Patients who are without sight have no ocular align-
ment and commonly manifest a gross searching and
wandering nystagmus. Nystagmus in the rst year of
life suggests bilateral vision loss until proved other-
wise. In infancy, vision loss is a common cause of
nystagmus.
Visual Fixation
Even though the visual system is incompletely devel-
oped at birth, most infants can see and will demonstrate
visual interest when stimulated by a human face. At
birth the infant will have visual xation present, and by
2 months of age xation will be well developed. Any
parental concern about a child’s visual functioning is an
important history nding.
Is this an emergency that requires
immediate intervention?
What is the extent of vision loss?
Key Questions
n What can you see? Can you detect light?
n Is your vision blurred?
n To self: Does the patient look at me?
n If a child: Does the child’s eye wander?
Total Absence of Vision
Disease that affects the optic nerve or retina, such as
retinal detachment, leads to total loss of vision.
Blindness is a complete lack of form and visual light
perception.
Key Questions
n Was the loss of vision sudden?
n Is the loss in one or both eyes?
n Is the loss complete or partial?
n Is there any pain with the loss of vision?
n Are there other symptoms associated with the loss,
such as a ash of light?
n Was the loss momentary or persistent?
Onset
Sudden loss of vision suggests a vascular etiology,
specically occlusion of the central retinal artery
until proved otherwise. In occlusion of the central
423
424 Chapter 35 • Vision Loss
Left
Visual fieldsRight
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retinal artery, the patient notes that vision is lost
suddenly, and light cannot be distinguished from
dark. Loss of vision in one eye indicates that the
problem is anterior to the chiasm; hemianopic eld
defects in both eyes suggest a postchiasmal lesion
(Figure 35-1).
Occlusion of the artery is an emergency and
requires immediate treatment.
A
B
C
D
E
Pain
Sudden loss of vision with eye pain and photophobia
indicates pathology of the cornea, iris, and ciliary
body. Sudden loss of vision with a red painful eye may
indicate acute-angle glaucoma (see Chapter 27). Inammation, demyelinization, or degeneration of the
optic nerve causes pain on movement of the eye and is
thought to be the result of general inammation of the
Left
Right
A—Total blindness of right eye
B—Bitemporal hemianopsia
C—Left nasal hemianopsia
D—Left homonymous hemianopsia
E—Left homonymous hemianopsia
inferior quadrant
F—Left homonymous hemianopsia
superior quadrant
FIGURE 35-1 Visual fields and examples of visual field defects along the optic nerve, optic chiasm,
optic tracts, and optic radiations in the cortex. (From Rudy EB: Advanced neurological and neurosurgical
nursing, St Louis, 1984, Mosby.)
F
Optic nerve
A
B
C
D
E
F
Visual cortex
Optic chiasm
Optic tract
Optic radiation
Chapter 35 • Vision Loss 425
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posterior portion of the orbit or inammation of the
optic nerve (cranial nerve II). Retrobulbar neuritis is
the most common disease in this category.
A common cause of sudden loss of vision without
pain is vitreous hemorrhage. The patient describes oaters that begin to drift in front of the eye, followed by a
red glow. The vision gradually fades until only light and
dark are distinguished. Painless vision loss is also associated with macular degeneration, retinal detachment, diabetic retinopathy, and anterior ischemic optic neuropathy.
Other Symptoms
In children, acute optic neuritis rarely occurs as an isolated condition and is usually a manifestation of a neurological or systemic disease such as meningitis, viral
infection, or demyelinizing diseases. It may also be associated with lead poisoning and long-term use of certain
drugs, most notably chloramphenicol or vincristine.
Flash of Light with Loss of Vision
Patients who have retinal detachment describe a ash
of light shortly before loss of vision. Some patients
describe a veil over the eye either just before or immediately after the ash. The reason for the ashes is
that detachment of the retina causes mechanical stimulation of the rods and cones as it tears away from the
pigment epithelium and oats free.
Patients whose retinae pull away or tear but do not
detach experience the same ash of light as those with
retinal detachment. They may also experience momentary total or partial loss of vision in the affected eye.
Transient Loss of Vision
Some patients with migraine headache experience
a scotoma, or an area of impaired vision within the
visual eld, before the onset of the headache. The scotoma may be either positive (the patient sees a
light spot or scintillating ashes [e.g., scintillating
scotoma]) or negative (the patient experiences a blind
spot). Scotoma may be prodromal to a migraine headache. Profound anxiety can produce a transient loss of
vision or a perceived loss of vision.
Can I rule out trauma?
Key Questions
n Is there a history of head trauma?
n Is there a history of eye trauma?
n Has there been a chemical or thermal injury?
Head Trauma
Loss of vision is most likely to occur after trauma to
the occiput. The vision loss is sudden and complete,
but vision usually returns in a matter of hours. Severe
head trauma with skull fracture but without direct damage to the eyeball can result in loss of vision that
occurs immediately or shortly thereafter. Occasionally
a patient can have good vision in the affected eye after
the accident and subsequently loses vision as a result
of severe retrobulbar hemorrhage. In children, trauma
is the most common cause of retinal detachment.
Shaken baby syndrome may result in retinal and vitreous hemorrhage.
Eye Trauma
Blunt trauma occurs when an object impacts the bony
orbit of the eye. High-velocity injuries to the eye are
not always immediately obvious. Small perforations or
penetrations of the cornea may appear similar to corneal abrasions. Sharp trauma includes impact from a
sharp object that may perforate the cornea, leaking uid
from the eye.
Cataract formation is a result of major trauma to the
eye in children. Opacication of the lens can result
from a blunt or penetrating injury.
Chemical or Thermal Trauma
Alkaline burns from household cleaners and lawn and
garden products can cause irreversible vision loss. Exposure to extreme heat or ames can damage the cornea
and eyelids.
Minutes make a difference with chemical trauma to
the eye—treat rst and examine later. Wash the eye
with water or normal saline solution immediately.
Is the vision loss because of a chronic
problem?
Key Questions
n How long has vision loss been present?
n Has vision decreased over time?
Progression of Vision Loss
Slowly progressive degenerative disease of any part
of the eye can cause progressive vision loss. Progressive loss of visual acuity and color vision can
be seen with optic gliomas, the most frequently
occurring tumor of the optic nerve in childhood. A
history of neurobromatosis can be found in 25% of
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patients. Children who have surgery for cataracts are
especially at risk for glaucoma. Glaucoma may cause
chronic loss of vision. Age-related macular degeneration is associated with decreased reading vision (see
Chapter 27).
Is this related to a genetic, familial,
or intrauterine risk?
Key Questions
n Is there a family history of vision or eye problems?
n Is there a history of maternal, intrapartum, or neonatal
conditions?
Family History
A family history of retinoblastoma, congenital cataracts, or metabolic or genetic disease is a risk factor for
visual and ocular abnormalities. Retinoblastoma occurs
in 12% of children with a family history. Hereditary
congenital cataracts occur in 10% to 25% of children
with a family history. Autosomal dominant inheritance
is the most common cause.
Maternal, Intrapartum, and Neonatal Risks
Infants at risk for vision problems are those who
are premature; have been on oxygen therapy; are low
birth weight; or have mothers who have had infections
related to HIV/AIDS and toxoplasmosis, rubella,
cytomegalovirus, and herpes simplex—known as the
TORCH complex of infections. These conditions
during pregnancy may produce blindness at birth
or vision loss later in life. Down syndrome is associated with cataracts. Children with galactosemia develop cataracts in infancy. Children with galactokinase deciency develop cataracts in the rst decade
of life.
Is the loss because of a systemic disease?
Key Question
n Do you have a chronic disease?
Chronic Disease
Diabetic retinopathy is a leading cause of vision loss. It
is a progressive condition resulting from incompetent
arterioles or microinfarctions and allowing hard exudates
to leak into the retina. The risk of retinopathy increases
with the duration of diabetes. Neurodegenerative disease
and juvenile rheumatoid arthritis can cause visual
changes. Prolonged treatment with systemic steroids
almost invariably results in the formation of posterior
subcapsular cataracts. Marfan syndrome may cause dislocated lens.
Could this be an anatomical problem?
Key Questions (to self)
n Do the eyes cross?
n If a child: Does the child squint, especially in the sun?
n Do the eyes appear symmetrical?
n Are the eyes bulging or sunken?
Eye Alignment
Amblyopia is impaired vision in an eye that appears
to be structurally normal. It is dened in one of the
following three ways:
1. Strabismic amblyopia occurs when one eye is out
of alignment and the fovea of that eye receives an
image that is different from that received in the
opposite eye. The brain suppresses the image in
the deviating eye to avoid diplopia and visual
confusion.
2. Refractive amblyopia occurs when the refraction of
each eye is so different that the child uses the eye
that focuses the best, resulting in poor development
of the other eye.
3. Deprivation amblyopia is anything that prevents an
image from being received clearly by the retina.
Conditions such as severe ptosis, congenital cataracts, or vitreous opacity may cause this.
Squinting
Squinting blocks out the outer rays from the object,
resulting in a smaller amount of distortion, and increases the chance of being able to more clearly perceive the image on the retina. This often occurs with
strabismus. Excessive squinting in bright light may
indicate glaucoma.
Exophthalmos
Bilateral exophthalmos is protrusion of the eyeballs
that occurs with hyperthyroidism. Lid lag is observed
on downward gaze as a lag in the falling of the lid
with the globe as it moves downward. Unilateral
exophthalmos may indicate a tumor located behind
the eye.
Enophthalmos
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Enophthalmos is the backward displacement of the
eyeball in the eye socket, leading to a sunken appearance. It is caused by starvation, dehydration, or trauma.
Ptosis
With ptosis, the eyelid margin is at or below the pupil.
The eyelid appears to be drooping and interferes with
vision. Ptosis may indicate a lesion of the oculomotor
nerve (cranial nerve III), a neuromuscular weakness, or
a congenital condition.
Is there a pattern to the vision loss?
Key Question
n When does the vision loss occur?
Pattern of Vision Loss
Retinitis pigmentosa is characterized by progressive
disorganization of the pigment of the retina, usually
accompanied by a decrease in the number of retinal
vessels and some degree of optic atrophy. Night blindness is often the rst symptom of vision loss. A progressive loss of vision may occur over decades. Dimming of vision upon standing can occur in someone
with low blood pressure or impending shock.
Individuals who are extremely myopic often experience a reduction in vision at nighttime and may refer
to that condition as “night blindness.” Vitamin A deciency or the result of retinotoxic drugs, such as quinine,
can cause night blindness.
Chapter 35 • Vision Loss 427
Developmental Delay
Decreased vision can result in developmental delays.
Motor development requires good visual cues and
depth perception. Poor school performance may be the
rst indication of vision loss related to refractory errors
and progressive myopia in some children. Craniopharyngiomas can compress the optic nerve system, causing a decrease in visual acuity and a decrease in school
performance (Box 35-1).
Box 35-1
Normal Development of Vision
and Eye Movements
Age Normal Vision and Eye Movements
Birth (term) Fixation
Poor following
Intermittent strabismus frequently
present
Visual acuity 20/400 to 20/600
1 mo Horizontal following to midline
Normal alignment
Visual acuity 20/300
2 mo Vertical following begins
Normal alignment
Visual acuity 20/200
3 mo Good horizontal and vertical following
Normal alignment
Visual acuity 20/100
Accommodation begins
Binocularity detectable
6 mo Visual acuity 20/20 to 20/30
Binocularity well developed
8 to 10 yr End of sensitive period for amblyopia
From Monte M: The eye in childhood, Am Fam Physician 60:907,
1999.
Can I associate the vision loss with the age
of the patient?
Key Questions
n What is your age?
n If a child: Is there a history of developmental
delay?
n If a child: Is there a change in school performance?
Vision Loss with Aging
Age-related macular degeneration is the leading cause
of permanent blindness in older adults. The prevalence
increases with each decade over 50 years to almost
35% by the age of 75. The majority of adults over
50 years have some degree of visual impairment.
DIAGNOSTIC REASONING:
FOCUSED PHYSICAL EXAMINATION
Children become increasingly threatened the closer
the examiner comes to the face. The least-threatening
assessment should be done rst.
Assess for Visual Acuity
Visual acuity for distance vision in adults and children
older than 4 years is tested using the Snellen or Tumbling E charts. Test each eye separately, with and without corrective lenses. Normal visual acuity tested using
a Snellen chart is 20/20 in the best eye without correction. A Snellen of 20/70 indicates visual impairment,
and vision that cannot be corrected to better than
428 Chapter 35 • Vision Loss
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20/200 is legal blindness. A Rosenbaum pocket card
held 15 inches from the eyes is used to test near or
reading vision.
To test for central vision in infants, observe the
infants’ eyes as they follow large objects, such as the
face or hand of the examiner, in various gazes. In children ages 1 to 3 years, use the cover/uncover test and
observe the corneal light reex.
Any child who has a difference of one line between
the two eyes must be referred. Vision of 20/50 for
5 year olds and 20/40 for children 6 years and older
requires referral. Retest using the Snellen chart before
referring because children tend to do better on a second
examination (Table 35-1).
Table 35-1
Pediatric Eye Evaluation Screening Recommendations for Primary Care
Assess Lids, Pupils, and Orbits
Note the position of the eyelids. Eyelids that droop
(ptosis) may cause vision loss. Assess for the symmetry of each eye, and observe for a transparent cornea.
The appearance of a white pupil (leukokoria) may
indicate a cataract, retinoblastoma, persistent hyperplastic primary vitreous (PHPV) retinal detachment,
vitreous hemorrhage, or intraocular inammation, such
as by Toxocara canis, which is a roundworm that is
contracted from dogs and invades the liver, abdomen,
and eyes.
Pupil size is smaller in infants and older adults. Five
percent of people will have noticeable differences in
Providers, Nurses, Physician’s Assistants, and Trained Lay Personnel
RECOMMENDED AGE
FOR SCREENING* SCREENING METHOD
Newborn to 3 mo Red reflex
Inspection Structural abnormality
6 mo to 1 yr Fix and follow with each eye Failure to fix and follow in cooperative
Alternate occlusion Failure to object equally to covering each eye
Corneal light reflex Asymmetrical
Red reflex
Inspection Structural abnormality
3 yr (approximately) Visual acuity
Corneal light reflex/cover-uncover Asymmetrical ocular refixation movements
Red reflex
Inspection Structural abnormality
5 yr (approximately) Visual acuity
Corneal light reflex/cover-uncover Asymmetrical/ocular refixation movements
Stereoacuity
Red reflex
Inspection Structural abnormality
Older than 5 yr Visual acuity
Corneal light reflex/cover-uncover Asymmetrical/ocular refixation movements
Stereoacuity
Red reflex
Inspection Structural abnormality
Reprinted with permission from the American Academy of Ophthalmology: Pediatric Eye Evaluations Preferred Practice Pattern, ©1997, American
Academy of Ophthalmology, Inc.
*Note: These recommendations are based on expert opinion.
†Physician or nurse responsibility.
‡Figures, letters, “tumbling E,” or optotypes.
§Optional: Random Dot E Game (RDE), Titmus Stereograms (Titmus Optical, Inc., Petersburg, VA), Randot Stereograms (Stereo Optical Company,
Inc., Chicago).
†
†
‡
†
‡
§
†
‡
§
†
CRITERIA FOR REFERRAL
TO AN OPHTHALMOLOGIST
Abnormal or asymmetrical
infant
Abnormal or asymmetrical
20/50 or worse or two lines of difference between
eyes
Abnormal or asymmetrical
20/40 or worse or two lines of difference between
eyes
Failure to appreciate stereopsis
Abnormal or asymmetrical
20/30 or worse or two lines of difference between
eyes
Failure to appreciate stereopsis
Abnormal or asymmetrical
Chapter 35 • Vision Loss 429
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pupil size (physiological anisocoria). However, many
types of central nervous system diseases also cause
differences in pupil size.
Enlargement of the pupil may be caused by ocular injury, acute glaucoma, systemic parasympatholytic drugs,
and dilating drops. Constriction of the pupil is seen in iris
inammation and patients with glaucoma who are treated
with pilocarpine. Irregularity of the pupil contour is invariably abnormal, occurring in iritis, syphilis of the
central nervous system, trauma, and congenital defects.
Inspect for Nystagmus
On far lateral gaze, some eyes will develop a rhythmic twitching motion (nystagmus) in the direction of
gaze followed by a drift back. This is a normal nding. However, nystagmus is a neurological sign that
may indicate disease or structural changes in the
vestibular-cerebellar-oculomotor system. Pathological nystagmus is seen when the movement is in the
same direction, regardless of the direction of gaze.
Nystagmus in the rst year of life suggests bilateral
vision loss until proved otherwise.
Assess Visual Fields
Testing of the visual elds assesses the function of the
peripheral vision and central retina, the optic pathways, and the cortex. The peripheral eld is damaged
in glaucoma and by tumors or vascular lesions involving the visual bers from the chiasm to the occipital
cortex. A central vision loss is decreased visual function surrounded by normal function. Hemianopsia is a
visual defect in the right and left halves of the visual
eld; this is due to a lesion involving the chiasm. In
homonymous hemianopsia, the same half of the visual
eld of each eye is affected by a lesion posterior to the
chiasm (see Figure 35-1).
the other eye was covered and a heteropia, or deviation
of an eye, is present. If the uncovered eye does not
move, alignment is present and this is referred to as
orthophoria. Repeat the test for the other eye.
Perform an Alternating Cover/Uncover
Test
Alternate the cover rapidly on each eye and note any
movement of the eyes. Perform this test to discover a
latent tendency for misalignment of the two eyes, a
condition referred to as heterophoria.
Use the Amsler Grid
An Amsler grid is used to test for distortion of central vision. The patient is asked to wear reading
glasses, and the chart is held 15 inches from the
eyes. Ask the patient to stare at the dot and tell
you if the lines around the dot are curved or bent.
Distortion, called metamorphopsia, is found in agerelated macular degeneration or central vision loss
(Figure 35-2).
Test for Extraocular Movements
Extraocular movements test six pairs of ocular muscles and three cranial nerves (III, IV, and VI). Strabismus is any condition in which the normal binocular
alignment of the eyes to a single point in any and all
elds of gaze is disturbed; there is an imbalance
in neuromuscular sensory and motor control of the
extraocular muscles. Half of patients with strabismus
also have amblyopia.
Test Corneal Light Reflex
The corneal light reex test is used to detect strabismus.
Alignment of the eyes is most easily demonstrated by
observing the reection of a light on the cornea. The
light should fall in each eye at the same point. An asymmetrical light reex will be present in a deviating eye or
in an eye with an asymmetrical contour.
Perform a Cover/Uncover Test
Have the patient look with both eyes at a specic point.
With one eye covered, watch the uncovered eye. If this
eye moves to x on the point, it was not aligned before
FIGURE 35-2 Example of metamorphopsia and a scotoma
projected on an Amsler grid. (From Hampton GR, Nelson PT:
Age-related macular degeneration principles and practice,
New York, 1992, Raven Press.)
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Paralytic strabismus is a deviation in the direction
opposite the muscle involved. Double vision is usually a symptom but may not be present if the condition occurred at an early age and the child suppressed
the vision in one eye or developed a compensatory
head malposition.
Nonparalytic strabismus is present when the angle
of deviation is the same in all cardinal elds of gaze.
Obtain a Direct and Consensual Pupillary
Response
In monocular blindness, the affected eye will have no
direct pupil response but will react consensually to
stimulation of the opposite eye. Stimulation of the
blind eye, however, will not cause consensual reaction
of the opposite normal eye.
Perform an Ophthalmoscopic
Examination
Examination of the optic disc can rule out optic atrophy, papilledema, and glaucoma. Death of the bers of
the optic nerve results in disappearance of the vessels
of the disc, leading to pallor or whiteness of the disc.
Observe for a red light reex, especially in the early
days and months of life. If the red reexes are not
equal, refer to an ophthalmologist. To obtain a red reex in a newborn or young infant, swaddle and then
hold the child. Position the ophthalmoscope diopter at
0, direct it to the eye, and gently swing or slightly parachute the infant. The vestibular system usually triggers
the infant’s eyes to open because of the maneuver.
In older children and adults, darken the room and
instruct the patient to stare at an object or a glow
sticker in the distance. When the patient looks at the
ophthalmoscope light, look at both red reexes simultaneously and compare them. A uniform red glow
equal in color is normal. Absence of a red reex indicates that some abnormality is blocking the transmission of light through the eye.
The earliest sign of papilledema is a hyperemic disc
caused by increased venous pressure. The dilated vessels leak their contents. The uid leak causes elevation
of the disc, which may spread beyond the disc margins,
making the edges of the disc appear swollen or indistinct. In glaucoma, one sees a glaucomatous cup. The
disc edge appears to be displaced slightly backward,
causing a cup shape.
Hemorrhages scattered in the vitreous cavity tend to
disperse and absorb light. A red reex is not seen; only
darkness will be seen. This is a common nding in
advanced diabetic retinopathy.
LABORATORY AND DIAGNOSTIC STUDIES
Ophthalmoscopy with Pupillary Dilation
Direct ophthalmoscopy allows a view into the retina and
optic nerve. More of the peripheral posterior segment is
seen when the eye is dilated with a mydriatic drug.
If the iris seems abnormally close to the cornea, dilation is contraindicated because of the risk of inducing
acute-angle closure glaucoma.
Tonometry
A tonometer is a device that measures intraocular pressure. Intraocular pressure greater than 21 mm Hg is
considered a high-risk factor for glaucoma.
Fluorescein Dye
Fluorescein dye is used to detect the presence of abrasions or a foreign body on the corneal surface. If the
corneal epithelium has been disturbed, uorescein will
pool within these areas and stain the hydrophilic
stoma. A stain showing a dendritic pattern indicates
herpes infection.
DIFFERENTIAL DIAGNOSIS
Early detection and treatment of vision and eye diseases
yield immense benets.
Strabismus and Amblyopia
The most common causes of vision loss in children are
amblyopia and strabismus. Amblyopia, or lazy eye, is
reduced visual acuity in one eye that is not correctable
with lenses. It is caused by incomplete visual system
development when a refractive error is not corrected in
childhood. Strabismus is a condition in which the
two eyes do not point in the same direction when the
patient is looking at a distant object. These conditions
cause vision loss in 2 out of every 100 children. The
risk of the development of amblyopia is greatest during
the rst 2 to 3 years of life, but the potential for recurrence exists until visual development is complete at
9 years of age.
Refractive Errors
Refractive errors are a common visual disorder of
childhood, occurring in 20% of children by 16 years of
age. Permanent visual impairment may result if optical
correction is not provided at an appropriate age.
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