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Chapter 38 • Vision Loss
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449
Is the loss because of a systemic disease?
Key Question
l
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 uncontrolled diabetes.
Neurodegenerative disease and juvenile idiopathic arthritis can cause vision 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)
l
Do the eyes cross?
l
If a child: Does the child squint, especially in the
sun?
l
Do the eyes appear symmetrical?
l
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 perceive the image
on the retina more clearly. 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
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
l
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.
Can I associate the vision loss with the age of the
patient?
Key Questions
l
What is your age?
l
If a child: Is there a history of developmental delay?
l
If a child: Is there a change in school performance?
Vision Loss With Aging
AMD 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.
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Chapter 38 • Vision Loss
The majority of adults over 50 years have some degree
of visual impairment. The incidence of cataracts increases with age. By age 80, more than half of all
Americans either have a cataract or have had cataract
surgery.
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 38-1).
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
Box 38-1
AGE NORMAL VISION AND EYE MOVEMENTS
Birth (term) Fixation
1 mo Horizontal following to midline
2 mo Vertical following begins
3 mo Good horizontal and vertical following
6 mo Visual acuity 20/20 to 20/30
8 to 10 yr End of sensitive period for amblyopia
From Del Monte M: The eye in childhood, Am Fam Physician 60:907,
1999.
Development of Vision and Eye
Movements
Poor following
Intermittent strabismus frequently present
Visual acuity 20/400 to 20/600
Normal alignment
Visual acuity 20/300
Normal alignment
Visual acuity 20/200
Normal alignment
Visual acuity 20/100
Accommodation begins
Binocularity detectable
Binocularity well developed
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
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 in-
fant’s 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 38-1).
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 retinal detachment, vitreous
hemorrhage, or intraocular infection, 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
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
finding. However, nystagmus is a neurological sign
that may indicate disease or structural changes in
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Table 38-1
Pediatric Eye Evaluation Screening Recommendations for Primary Care
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
Alternate occlusion Failure to object equally to covering each
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
Modified from the American Academy of Ophthalmology Pediatric Ophthalmology/Strabismus Panel. Preferred Practice Pattern® Guidelines. Pediatric Eye Evaluations. San Francisco, CA: American Academy of Ophthalmology; 2007.
*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
Failure to fix and follow in cooperative
infant
eye
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
EVIDENCE-BASED PRACTICE
The purpose of this systematic review was to measure the
diagnostic accuracy of examination findings and risk factors in identifying individuals with prim ary open-a ngle
glaucoma (POAG) because early identification ma y prevent associated vision loss. The prevalence of glaucoma
in the studies was 2.6% (9 5% CI, 2.1 %-3.1%). Myopia
of $6 diopters and family history of glaucoma were
risk factors that had the strongest association with glaucoma. Demographic factors associated with an increased
Reference: Hollands H, Johnson D, Hollands S, Simel DL, Jinapriya D, Sharma S: Do findings on routine examination identify patients at risk for
primary open-angle glaucoma? The rational clinical examination systematic review. JAMA 309:2035, 2013.
Should Adults Have Routine Screening for Glaucoma?
risk were Black race and increased age (especially age
.80 years). Other risk factors included an increased
cup-to-disc ratio (CD R), CDR asymmetry, disc hemorrhage, and increased intraocular pressure. The authors
found no studies of screening examinations pe rformed by
generalist physicians in a routine setting and conclude
that the evidence supports examination by an ophthalmologist or optometrist as the most accurate way to detect
glaucoma.
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Chapter 38 • Vision Loss
the vestibular-cerebellar-oculomotor system (see
Chapter 13). Pathological nystagmus is seen when
the movement is in the same direction, regardless
of the direction of gaze. Nystagmus in the first 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 caused by 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 38-1).
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
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.
metamorphopsia, is found in AMD or central vision
loss (Figure 38-2).
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.
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 optic
nerve bers results in disappearance of the vessels of
the disc, leading to pallor or whiteness of the disc.
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
FIGURE 38-2 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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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.
Myopia (nearsightedness) is when the cornea and
lens of the eye focus the image in front of the retina.
Hyperopia (farsightedness) is a refractive error in which
the focus of an image is behind the retina. Hyperopia
can be corrected to some degree by adjustment of the
natural lens (accommodation) normally done for nearfocusing. The use of accommodation can cause visual
fatigue, discomfort, and headache.
Astigmatism
Astigmatism is an irregularity in the refractive system of the eye that prevents light from being focused
onto the retina. It can be secondary to the shape of
the cornea or lens and is usually correctable with
lenses.
Cataracts
A cataract is any opacity of the crystalline lens of the
eye. There are many causes of cataracts and they can
be dened by onset, cause, or anatomy.
Congenital cataracts are inherited in an autosomal
dominant form and are associated with intrauterine
infections by the TORCH complex of organisms. Cataracts of infancy and childhood occur in 1 per 1000 live
births and congenital glaucoma occurs in 1 per 10,000
live births.
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Chapter 38 • Vision Loss
Adult cataracts are a major cause of visual impairment in the elderly because with time, the human lens
begins to develop opacities. Cataracts can be caused by
galactosemia, metabolic disorders (e.g., diabetic cataracts), and trauma (e.g., from heat or blunt trauma);
steroid-induced cataract formation is also possible. The
rst signs of opacity are the inability to focus on near
objects (presbyopia) and altered color vision.
Optic Neuritis
Optic neuritis occurs more often in younger adults, 20 to
50 years old, and in women; it is typically monocular.
It is often idiopathic and may be associated with
multiple sclerosis, after viral infection, and with granulomatous inammatory conditions. Vision loss occurs
over a few hours to days and is extremely variable.
Visual eld loss includes central scotoma in 90% of
patients. In the majority of patients, pain precedes the
vision loss and is worse with eye movement.
Optic Nerve Hypoplasia
This visual disorder affects the optic nerve, the bundle
of bers that transmits signals from the retina to the
brain. It is a nonprogressive disorder in which the optic
nerve is 25% smaller than the normal size. Some children have a loss of peripheral vision although others
lose central vision.
Injury
More than 100,000 eye injuries occur annually in the
general population of the United States, of which 90%
are preventable with the use of protective eyewear.
Exposure to long periods of high heat or blunt trauma
to the eye globe can result in cataracts.
Retinoblastoma
This is the most common intraocular tumor of childhood; it occurs bilaterally in 30% of cases. A common
symptom is strabismus. Retinoblastoma is inherited in
an autosomal dominant manner. Early lesions are at,
transparent, or white masses in the retina. The tumor
can spread to the brain through the optic nerve or into
the bone marrow.
have incomplete vascularization with subsequent poor
vessel development and visual impairments. Infants
who weigh less than 1500 g are at greatest risk.
Central Retinal Artery Occlusion
Patients with this condition have a sudden onset of
severe vision loss in one eye. There is no associated
pain. The loss is caused by plaque lodging at the level
of the lamina cribrosa. On physical examination a few
hours after occlusion, the retina becomes edematous
and white or opaque. There is a reddish-orange reex
from the intact choroidal vascular and foveola that
creates a “cherry red spot” that contrasts with the
surrounding white retina. With time, the retinal artery
opens and the retinal edema clears.
Glaucoma
Glaucoma is loss of vision because of increased pressure in the eye. It is characterized by defects in the
visual eld and optic nerve damage. Glaucoma is a
leading cause of blindness in the United States.
Glaucoma can be classied as primary or secondary,
and as open- or closed-angle. Secondary glaucoma is
associated with another ocular or nonocular event;
whereas primary glaucoma is not. Closed-angle glaucoma is caused when the anterior chamber angle is
narrowed, reducing the outow and removal of aqueous humor. Open-angle glaucoma, the most common
type, occurs with a normal anterior chamber angle.
The condition is painless, and symptoms appear in
late stages of the disease. Ophthalmic examination
reveals pathological cupping of the optic disc that
may be asymmetrical. Patients with intraocular
pressures above 21 mm Hg should be referred to an
ophthalmologist (Box 38-2).
Retinal Detachment
This condition occurs when the neurosensory retina is
separated from the retinal pigment epithelium. About
half of patients will have brief ashes of light (photopsia) or oaters (entopsia). It is caused by a collection
of uid beneath the neurosensory retina, traction
from brovascular elements associated with diabetic
Retinopathy of Prematurity
This condition is seen in premature infants and refers
to the changes of ischemia, blood vessel growth, and
brosis that occur because of inadequate oxygen delivery to the peripheral retina. The vessels of the retina
normally complete vascularization by 40 weeks of
gestation. Infants who are born before this time may
Box 38-2
Visual acuity should be assessed intermittently after age
40 with no optimal interval recommended. Routine screening
for glaucoma by primary care providers is not recommended.
Adult Vision Screening
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retinopathy, or trauma. Nearly 95% of detachments are
treatable.
Macular Degeneration
AMD is the leading cause of blindness in the United
States. It may be asymptomatic or associated with
gradual loss of central vision. Risk factors include
advanced age, family history, cigarette smoking, hy-
peropia, and hypertension. There are two forms of
pathological macular degeneration, wet and dry. The
wet (exudative) form results in rapid vision loss
caused by the development of abnormal blood vessels
that grow from the choroid into the macular portion of
the retina. These new blood vessels, called choroidal
neovascularization, are very fragile and often leak
blood and uid. Blurred vision is a common early
symptom but vision loss may be rapid and severe. The
dry (nonexudative) form is associated with breakdown
of the light-sensitive macular cells and gradual loss of
central vision. Distortion upon testing with the Amsler
grid is found with dry AMD. Both types can occur in
the same eye.
Diabetic Retinopathy
Diabetic retinopathy is a retinovascular disease that
occurs in two forms. Nonproliferative retinopathy is
characterized by microaneurysms, macular edema,
lipid exudates, and intraretinal hemorrhages. In pro-
liferative retinopathy, blood vessels regenerate on
the retina. The patient may be asymptomatic or have
decreased vision or oaters. Diabetic retinopathy
progresses with the duration of diabetes.
Uveitis
Uveitis is a general term used to describe inammatory
activity of the iris, ciliary body, and choroid. Symp-
toms vary according to cause and severity, but most
patients experience some decrease in vision, light
sensitivity, and tearing. Pain may be variable. Acute
uveitis lasts less than 3 months but it may have a
chronic recurrent pattern.
infection, dry eyes, physical and chemical injury, and
systemic disease. Keratitis can range from mild to severe and can be chronic. Diagnosis is usually made by
an ophthalmologist using a slit lamp.
Optic Nerve Glioma
Optic nerve gliomas are present in two forms. In the
adult, they are malignant glioblastomas; in the child,
they are benign pilocytic astrocytomas. They appear in
children younger than age 10 and are highly associated
with neurobromatosis, a condition associated with
café-au-lait lesions of the skin. In children, gliomas
may appear as the rapid onset of vision loss with headache. Of the malignant optic nerve gliomas, nearly
75% present with unilateral, rapidly progressive vision
loss with pain.
Craniopharyngioma
Craniopharyngiomas are tumors that arise from
squamous epithelial cells of the brain. They are
most common in the first two decades of life but
also may occur in adults 50 to 70 years old. Children’s presenting symptoms include headache and
visual disturbance caused by increased intracranial
pressure. Nystagmus and bitemporal hemianopsia
are pathognomonic for this tumor. In the older
patient, visual deficit is common in the presence of
normal optic discs.
Chemical or Thermal Trauma
A chemical burn is an ophthalmic emergency. Alkaline
solutions denature eye proteins and lyse cell membranes, allowing the chemical to penetrate the eye.
Acid burns can also cause severe damage, but the acid
solution precipitates proteins, decreasing the amount
of penetration damage.
Congenital Infection
Congenital TORCH infections can cause vision problems in infants. Postnatal screening is performed to
diagnose a TORCH infection.
Keratitis
Keratitis is an inammation of the cornea that creates
pain, redness, and blurred vision. It can be caused by
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DIFFERENTIAL DIAGNOSIS OF
Common Causes of Vision Loss
CONDITION HISTORY PHYSICAL FINDINGS DIAGNOSTIC STUDIES
Strabismus Family reports child’s eyes
cross, family history
Amblyopia May have history of premature
birth, Down syndrome, cere-
Refractive errors Sitting close to television,
Cataracts Blurred vision, glare, distortion
Optic neuritis History of multiple sclerosis,
Optic nerve hypoplasia History of vision loss, may
Injury, penetrating injury History suggesting head or eye
Retinoblastoma
Nystagmus
Retinopathy
of prematurity
Central retinal artery
occlusion
Glaucoma
Retinal detachment
Macular degeneration Older than 60 yr, decreased
Diabetic retinopathy History of diabetes, floaters,
Uveitis
bral palsy, hydrocephalus
squinting
and change in color perception, increased age, history
of infection, trauma, or
chronic disease
viral infection, pain with eye
movement, rapid vision loss
have central vision but no
peripheral vision
trauma (blunt or sharp)
Family history, child up to
2 yr old
History of eyes moving
repetitively, searching
Premature birth ,36 wk,
weight 1500 g, oxygen
administered, may be a twin
Sudden onset of painless
vision loss, may come
and go
Most often painless, gradual
vision loss, blurring, and
halos; more common in
older adults; history of
systemic disease
Sensation of flashing light
accompanied by shower of
floaters; history of trauma
to head or face
central vision, blue eyes,
image larger in one eye
gradual vision loss
History of infection or chronic
inflammation, mild to
moderate pain, photophobia, tearing
Extraocular movements
abnormal, cover/uncover
test positive
Vision decreased in one eye Refer
Loss of visual acuity
Whitish appearance of pupil,
bilateral or unilateral
Decreased visual acuity,
reduced color perception,
afferent pupil defect and
central scotoma
Optic nerve is one half to one
third normal size, pale to
gray in color, surrounded
by yellow halo
Directed by history Refer
Partial or absent red reflex,
strabismus
Rhythmic, repetitive
oscillation of eyes
Abnormalities of retinal
vessels
Macular edema, cherry
red spot; may see vessel
narrowing
Decreased visual acuity; may
have increased intraocular
pressure on palpation of
eye globe
Retina markedly elevated;
appears gray with dark
blood vessels; may lie in
folds
Hyaline (drusen) deposits
on retina near macula,
gray-green areas of
pigment under retina,
decreased visual acuity
Venous dilation, retinal
hemorrhages
Findings vary according to
cause and severity
Refer
Screen with Snellen,
Tumbling E, or
figures; refer
Refer
Refer
Refer
Refer
Refer
Refer
Refer
Refer for tonometry
Refer
Amsler grid
Refer
Refer
Chapter 38 • Vision Loss
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DIFFERENTIAL DIAGNOSIS OF
Common Causes of Vision Loss—cont’d
CONDITION HISTORY PHYSICAL FINDINGS DIAGNOSTIC STUDIES
Keratitis History of infection, trauma,
mild to severe pain, blurred
Optic nerve glioma Dimness of vision with loss of
Craniopharyngioma
Chemical burn
Thermal burns History of exposure to high
Congenital infections
TORCH, Toxoplasmosis, rubella, cytomegalovirus, and herpes simplex.
vision, itching with blinking
fields; may be unilateral
rapid vision loss with pain
Unilateral vision loss, head-
ache, child or adult
History of acid or alkaline
exposure
heat, occupational risk
TORCH, maternal exposure
to measles
References and Readings
Bell A, Rodes M, Collier Kellar L: Childhood eye examination, Am
Fam Physician 88:241, 2013.
Harvey PT: Common eye diseases of elderly people: Identifying and
treating causes of vision loss, Gerontology 49:1, 2003.
Marx JA, Hockberger RS, Walls RM: Rosen’s emergency medicine:
Concepts & clinical practice, ed. 8, St. Louis, 2014, Elsevier.
McPhee SJ, Papadakis MA: Current medical diagnosis and treat-
ment, ed. 49, New York, 2010, McGraw-Hill.
Norton I: Practical ophthalmology: A survival guide for doctors and
optometrists, Emerg Med Australas 17:524, 2005.
Conjunctivitis Refer for evaluation
with a slit lamp
Visual field defects, optic
atrophy
Funduscopic examination
may be normal
Treat first, then examine
Corneal opacities Refer
Retinitis, optic nerve
hypoplasia
Quillen DA: Common causes of vision loss in elderly patients, Am
Fam Physician 60:99, 1999.
Thompson L, Kauffman L: The visually impaired child, Pediatr Clin
North Am 50:225, 2003.
Tingley DV: Vision screening essentials: Screening today for eye
disorders in the pediatric patient, Pediatr Rev 28:54, 2007.
Walker S, Harris Z: Detecting the serious visual disorders of
childhood, Pediatr Child Health 22:25, 2011.
World Health Organization: Visual impairment and blindness, Fact
Sheet 282, April 2011. Retrieved from www.who.int/mediacentre/
factsheets/fs282/en/print.html.
Refer
Refer
Immediate eye
irrigation and
referral
Screen for TORCH,
refer
CHAPTER
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Weight Loss/Gain
39
nintentional weight loss is a decrease in body
U
weight that is not voluntary. Weight loss in the
adult is clinically signicant when it exceeds 5% of
usual body weight over a 6- to 12-month period.
Weight loss in the newborn may occur immediately
after birth but weight should begin to increase by
2 weeks of age. Weight loss will occur with reduced
energy (food) intake and increased metabolism or
energy output. Every day individuals adjust energy
balance to maintain a healthy weight through healthy
eating and regular physical activity. Malignancy and
endocrine disorders are the most common causes of
unintentional weight loss, followed by gastrointestinal
(GI), cognitive, behavioral, and functional disorders,
as well as age-related changes.
Weight gain occurs when caloric intake exceeds
body requirements, causing the body to store fat. Most
adults do not intentionally gain weight, but as we age,
a decrease in physical abilities leads to a decrease in
metabolic rate (amount of energy used in a given period), which in turn contributes to weight gain. Unexplained weight gain may be more difcult to identify,
especially in the United States, where 40% of men and
28% of women are overweight, 32% of men and 36%
of women are obese, and approximately 1 in 20 Americans have a body mass index (BMI) .40 kg/m
The prevalence of childhood obesity is increasing.
Unexplained weight gain may be endocrine-related,
age-related, or associated with cognitive impairments.
(Unintentional)
2
.
DIAGNOSTIC REASONING: FOCUSED
HISTORY
Unexplained Weight Loss
Has the patient lost weight? Is the weight loss really
unexplained?
Key Questions
l
How do you know that you (or the child) have lost
weight?
l
How old are you?
l
How is your appetite?
l
How would you describe your typical diet and activity
patterns?
l
If an infant: If breastfeeding, how is breastfeeding
going?
l
If an infant: If feeding formula, what kind is it and
how do you prepare it?
Measuring Weight
Individuals might note that their clothes are too loose
or too tight. Weight is usually measured by asking the
patient to step on a balance or electric scale clothed
and without shoes. Height is measured by asking the
patient to stand with the back against a wall with heels
touching the wall. There are several ways to classify
and measure body weight, but the most commonly
used method is the BMI formula, which is BMI 5
weight (kg)/height (m2). To enhance the reliability of
measurement of weight changes, ask the patient to
weigh himself or herself at the same time each day
using the same scale.
Weight and height in infants and children is measured using a scale and plotted on a National Center for
Health Statistics growth chart. Infants and children
should be measured in a supine position until the age
of 2 years. Head circumference is also measured and
plotted.
Age
Aging can be associated with both weight loss and
weight gain. Normally with aging there is less lean
muscle tissue, fat is deposited more in the trunk and
less in the limbs, and metabolism slows. In the elderly
it is especially important to assess what medications
are being taken that could suppress appetite, cognitive
status, and memory. Functional limitations that may
impact nutrition include the ability to chew and swallow, prepare meals, and shop for food. Social isolation
can also contribute to eating less.
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