The birth process can be somewhat traumatic to the eyes. Many newborns sustain episcleral and retinal hemorrhages during vaginal delivery (see Fig. 4-14). These hemorrhages can be alarming to both parents and physicians but are harmless and usually disappear within 2 weeks. At birth, the nasolacrimal duct often is blocked at its junction with the nasal mucosa under the inferior turbinate. The blockage resolves spontaneously in more than 90% of cases, although it can remain until 1 year of age in some children, causing persistent tearing. A few affected children then need surgical treatment.

The process and rate of development of vision in infants are better understood than they were 10 years ago. Vision exists in several forms with different neuronal channels carrying specific visual functions, such as contrast sensitivity, orientation, movement, and hyperacuity. Each function develops at a different rate. For practical purposes, normal newborns can see a human face easily and demonstrate their visual ability by looking at it; they even follow the face with eye or head movement as it passes slowly before them at close range (Fig. 8-1). A baby’s ability to follow your face can be verified only when the baby is awake and alert, often just before or in the middle of a feeding session. This innate ability is paramount to the infant’s future development because few parents fail to form an emotional attachment to a little one who looks directly at them minutes after birth. By contrast, parents of a blind or strabismic infant who are unable to establish the interaction that comes with normal eye contact may have significantly greater difficulty developing the same level of emotional attachment to their offspring.

FIGURE 8-1 Face follow vision testing of a young infant. A, Hold the child at arm’s length with the head comfortably supported. The examiner’s face is lined up with the apparent direction of gaze of the child. B, Move your face slowly to the side and observe the response. This 2-month-old boy now has a good face follow; he received his contact lenses 2 weeks after cataract surgery.

By 3 months of age, babies enjoy looking at the human mouth and eyes and at simple, colored toys. A 1-year-old toddler’s vision is about half as good as the best attainable adult score. Three-year-olds can see at least 6/9 (or 20/30 in the American system) in each eye, and their visual acuity can be tested with charts specially designed for them (see the section in this chapter on the LH test). The numerical ratio 20/30 actually indicates that a 3-year-old can see at 20 feet what the average adult sees at 30 feet.

Key Point

Infants’ visual fields are good in the temporal area at birth; by age 6 months, they are comparable with the visual fields of adults.

Color vision is present from an early age. Newborns have color vision, although it is less sensitive than that of older infants. Newborns do not see faint colors well, if at all, but by 3 months of age, definite trichromatism is established. Babies of this age can differentiate between red, green, and yellow.

Binocularity, which confers the ability to see in three dimensions, has been proven to exist by 3 months of age, coinciding with the time the eyes finally maintain good alignment. This finding underlines the clinical significance of any persistent deviation of the eyes after age 3 months.

Eye movements may appear irregular, unbalanced, or disconjugate until the third month of life. Healthy newborns can display tonic movements of the eyes downward or upward. Sometimes, the eyes turn toward (esotropia) or away (exotropia) from each other.

Key Point

Remember that constant deviation of an eye in any direction, or persistent “jiggling” of one or both eyes, is abnormal at any age.

Pupillary movements are limited in the newborn and are almost impossible to examine thoroughly at that age. A good pupillary examination in older children demands cooperation and patience, because children can rarely stare fixedly at a distant target while an observer tries to evaluate their pupils by shining a bright light in them. The children look either at the light or anywhere else and change their accommodation continuously, keeping their pupillary diameter in constant flux and possibly preventing adequate assessment of light-induced responses.

Accommodation in the newborn is limited. From a practical viewpoint, consider the newborn’s focus as stuck at an adult arm’s length. Within a few months after birth, focus improves, and the child’s accommodative amplitude soon reaches remarkable proportions. For example, a 5-year-old can clearly see a plane in the sky and then switch in a fraction of a second to look with great intensity at the details of a tiny spider close at hand. Unfortunately, this marvelous accommodative ability does not last forever.

Finally, a word on media transparency. The extraordinary transparency of all the optical parts of the child’s eye provides the observer with a crisp and bright image of the retina when viewed up close with the direct ophthalmoscope (a difficult but rewarding technique ). It also enables the clinician to critically assess the integrity of the eye with the very simple red pupillary image (reflex) test. In the right conditions, a bright coloration in the pupil provides a clear path for a light beam to enter the eye, hit the retina, and bounce back. This is the reason why photo shots can become prime screening tools to detect severe eye diseases.

Key Point

A normal child’s eye shows a clear, pupillary red reflection when viewed in the proper conditions.

Definition of terms

As an aid to diagnosis, this section contains a brief glossary of diagnostic terms that summarize the features to look for in children with eye problems. Box 8-1 and Figure 8-2 show the tools used to examine the eyes; Table 8-1 lists definitions and acronyms.

FIGURE 8-2 Equipment for evaluating the visual system in children: your face, ophthalmoscope, otoscope, red nipple, visual acuity test kit, and short-acting mydriatic agent (tropicamide 1%).

Table 8-1 Ophthalmologic Shorthand *

Abbreviation/Acronym	Definition
Alt	Alternating strabismus; in almost all cases of strabismus, fixation (use of the eye to look at something) is with at least one eye at a time; if there is equal vision, the eyes will alternate fixation
APD	Afferent pupillary defect
CD	Corneal diameter
C/D ratio	Cup/disc ratio (cup size can be enlarged in persons with glaucoma)
CL	Contact lens
Comit	Comitant
E	Esophoria; the eye turns in only when there is interference with binocular vision (as with covering)
ET	Esotropia; one eye is turned in spontaneously
E(T)	Intermittent esotropia; the eye turns in only occasionally
IOL	Intra-ocular lens
IOP	Intra-ocular pressure
OD	Oculus dexter (Latin); right eye (English)
OS	Oculus sinister (Latin); left eye (English)
OU	Oculus uterque (Latin); each eye (English)
PERLA	Pupils equally reactive to light and accommodation
SLE	Slit-lamp examination
VA cc	Visual acuity with correction (with glasses or contact lens[es])
VA sc	Visual acuity without correction
X	Exophoria
XT	Exotropia; one eye turns out (exodeviation)
X(T)	Intermittent exotropia; the eye turns out only occasionally

* For example, a diagnosis of strabismus could be written as “Alt Comit X(T),” which would mean “alternating comitant intermittent exotropia.”

Amblyopia

Decreased vision in one or both eyes when no detectable or residual uncorrected organic or optical anomaly remains. Amblyopia is reversible if treated early enough (well before 9 years of age). It is severe if it develops early, as when it is caused by a congenital cataract or congenital ptosis. Occlusion amblyopia can occur if treatment such as patching of the sound (good) eye is too prolonged.

Blindness

Legal blindness is defined as vision of 6/60 (20/200) or less. Most assistance agencies for visually handicapped children use 6/24 (20/70) as the maximum vision cutoff for registration for their services. The leading causes of blindness vary dramatically in different regions of the world. Malnutrition, onchocerciasis, and trachoma are the culprits in many developing countries, whereas macular degeneration, glaucoma, diabetic retinopathy, amblyopia, trauma, and corneal herpes are generally responsible for legal blindness in developed countries. Eye injuries by BB guns are a leading cause of traumatic blindness in North American children, and many medical professional groups have proposed that these guns be regulated by legislation. Amblyopia, with a prevalence rate of 4% to 5%, is a significant cause of monocular blindness. Genetic diseases (involving mainly the optic nerve and retina), birth injury, and congenital defects (cataracts being the most common) are important causes of blindness in North American children, as are retinitis pigmentosa and albinism. With increasing survival of very low birth weight infants, retinopathy of prematurity (ROP) and optic nerve atrophy are making a comeback as significant causes of visual loss in children.

Cataracts

Cataracts are an important cause of leukocoria (white pupil, from the Greek; see Plate 8–2). Causes of pediatric cataracts include congenital rubella, metabolic disorders, and chromosomal anomalies. Cataracts can result from ocular inflammation (uveitis) or may accompany other ocular malformations. Many idiopathic cataracts are sporadic, but some are genetic. Some systemically administered medications cause cataracts. Steroids are common culprits, and they can cause glaucoma as well. Amblyopia in a child with a cataract is severe; therefore, cataracts in infants need immediate attention. Postoperative optical correction may require the use of contact lenses in infants, although intraocular lenses are becoming more popular in children older than 2 years.

Hemangioma (orbital, capillary)

Benign congenital tumors that grow rapidly when a child is between 1 and 6 months of age but tend to regress spontaneously later (Plate 8–4). Benign congenital tumors may cause severe amblyopia by pupillary obstruction, high astigmatism, or both. Early treatment is essential to preserve vision. Injection of steroids into the tumor, systemic treatment, glasses, and patching of the sound eye all may be necessary.

Hyperphoria, hypophoria, hypertropia, hypotropia

Vertical ocular deviations.

Hyphema

Bleeding into the eye’s anterior chamber (Plate 8–5). A trauma severe enough to cause a hyphema can involve other eye structures, leading to retinal detachment or injuring the trabecular meshwork of the iridocorneal angle and thereby causing glaucoma. Hyphema is the principal diagnosis in one third of eye traumas and is a major cause of ocular morbidity in children. Hyphemas rebleed in 6% of cases within 5 days of onset, causing further complications, but it may be possible to prevent rebleeding by decreasing physical activity and, in very selected cases, by administering systemic antifibrinolytic agents.

Laceration (cornea or globe)

A cut through the protective shell of the eye. Suspect a laceration if there is a history of trauma with a sharp object (a forceful blunt impact also can rupture the globe). Do not try to pry the lids open; doing so might expel the contents of the globe. Repair of a simple laceration of the cornea can be followed by astigmatism, an amblyogenic factor necessitating further intensive treatment, including contact lenses and patching.

Lacrimal duct obstruction (congenital)

Lacrimal duct obstruction is benign but is included in the differential diagnosis with congenital glaucoma. It resolves spontaneously in 90% of children by age 12 months but rarely thereafter.

Leukocoria

A white pupil (Plate 8–2). This finding has major clinical implications. The differential diagnosis includes retinoblastoma and cataract. Delaying treatment of the former leads to death; delaying treatment of a cataract causes permanent loss of vision.

Lymphangioma

A diffuse benign tumor of the orbit that often bleeds internally and is another cause of ptosis, proptosis, or both. Almost impossible to resect completely in childhood, lymphangioma is a cause of astigmatism and amblyopia (Fig. 8-4).

FIGURE 8-4 Lymphangioma of the right orbit with poor vision due to astigmatism caused by the mass effect of the lesion on the shape of the eye.

Myelinated nerve fiber layer

Abnormal presence of myelin around the superficial nerve fibers of the retina near the optic disc (Plate 8–6). It can be so extensive that the pupillary red reflex can be made to appear white (leukocoria). The vision is generally normal except when the macula is heavily involved.

Nystagmus

A descriptive term for jiggly, unstable, wiggly, or trembling eyes. In up to 90% of cases, an ophthalmic cause of nystagmus can be identified. It is mainly found when vision has been poor since early in life. Most causes are sensory, affecting the anterior visual pathway. The causes can be retinal (cone dystrophy, early retinitis pigmentosa, or congenital retinal toxoplasmosis scar); neuronal (optic nerve anomalies or early dystrophies); ectodermal (various forms of albinism); or even optical (cataract or corneal anomalies). In persons with nystagmus, the type of movement often is not indicative of any particular cause.

Ophthalmia neonatorum

In North America, neonatal ophthalmia once was principally caused by gonorrheal infection. Now, the most common causative organism is Chlamydia trachomatis. Staphylococcus pyogenes may cause outbreaks of conjunctivitis in newborn nurseries. Transient chemical conjunctivitis normally occurs after 1% silver nitrate prophylaxis in the newborn. The best agent for prophylaxis of gonococcal and chlamydial ophthalmia neonatorum continues to be debated.

Optic nerve hypoplasia

A common cause of congenital blindness in children. Optic nerve hypoplasia often is misdiagnosed as optic atrophy because secondary nystagmus (sensory) makes the hypoplasia difficult to visualize. The optic nerve head (disc) is smaller than normal (Plate 8–7). Look for CNS midline defects, including the involvement of the hypothalamic-pituitary axis with accompanying growth hormone deficiency (see Chapter 16).

Palsies (sixth, third, and fourth cranial nerves)

The extraocular muscles are innervated by various cranial nerves: the superior oblique by the fourth cranial nerve (also called the trochlear); the lateral rectus by the sixth cranial nerve; and all the others by the oculomotor nerve, the third cranial nerve, which also innervates the pupil and the ciliary body for accommodation. Any injury to these nerves induces a strabismus, the angle of which varies according to the direction of gaze—an incomitant strabismus. Typically, a head turn is seen in persons with sixth nerve palsy and lid ptosis in persons with third nerve palsy. Fourth cranial nerve palsy (trochlear) causes an ipsilateral hyperdeviation and a contralateral head tilt (see Fig. 8-3).

Periorbital cellulitis

Any inflammation around the orbit is cause for concern, and the differential diagnosis should include rhabdomyosarcoma (see later definition). When the orbital content is involved, ocular motility is decreased and the patient is at imminent risk of loss of vision. Haemophilus influenzae meningitis is an early complication in children younger than 5 years. Periorbital cellulitis (Plate 8–8) is most often associated with ethmoiditis in children who do not have a clear history of skin trauma or infection around the eye, and both computed tomography scanning and magnetic resonance imaging are invaluable for a clear evaluation of the best therapeutic regimen. This condition is far less common in areas of the world where Haemophilus influenzae B vaccine is used. Most cases of periorbital cellulitis require systemic antibiotic therapy.

Persistent hyperplastic primary vitreous (PHPV)

The presence of a unilateral dense residual vascularized glial frond of tissue that originates from the optic nerve disc and projects toward the back of the lens. It is the first tissue present in the eye required to initiate the growth of the lens. In PHPV, the lens is abnormal and cataractous, causing a leukocoria; the differential diagnosis of leukocoria includes other forms of cataract and retinoblastoma. PHPV is associated with microphthalmos and cataracts. The vessels in the back of the lens can bleed, inducing a very rare but diagnostic hemorrhagic cataract. PHPV is a progressive malformation that requires early surgery to save the eye and possibly restore its vision (Fig. 8-5).

FIGURE 8-5 Persistent hyperplastic primary vitreous is a cause of cataract. The fibrotic nature of the vascular membrane present behind the lens (the hyperplastic primary vitreous) causes traction of the ciliary processes, which become visible once the pupil is dilated.

Plexiform neurofibroma

A type of hamartomatous formation found in persons with neurofibromatosis. In the orbit, it is accompanied by sphenoid bone defects with herniation of the contents of the anterior fossa into the orbital cavity. This condition may or may not cause visual problems, such as strabismus, astigmatism, and optic nerve dysfunction (Fig. 8-6).

FIGURE 8-6 Plexiform neurofibroma of the left upper orbit. Such a hamartoma most often displaces the eye down, but in this case, the neurofibroma has not induced any strabismus; the corneal light reflexes are symmetric. Note the fullness of both upper and, to a smaller extent, lower lids.

Refractive amblyopia

Amblyopia is caused by the blurred image of a poorly focused eye (hyperopia, myopia, or astigmatism). This condition is found most commonly in 3- to 4-year-olds.

Retinitis pigmentosa

A generic term describing a variety of retinal degenerations, including choroidal degenerations, diseases of either type of photoreceptors, and syndromes involving other organ systems (e.g., Laurence-Moon-Biedl and Alström syndromes in which progressive retinal degeneration is associated with obesity and other systemic dysfunctions) (Plate 8–9). Most patients with retinitis pigmentosa experience a severe visual deficit at an early age.

Retinoblastoma

The most important cause of unilateral or bilateral leukocoria, retinoblastoma occurs in 1 in 15,000 births and often is also present with a strabismus or a red eye (Plate 8–10). The gene for this condition is located on the long arm of chromosome 13. Retinoblastoma is most curable if diagnosed early. Later death from a second malignancy is a major concern in bilateral and autosomal dominant familial cases.

Retinopathy of prematurity (ROP)

A proliferative disease of the retina in small premature babies that involves abnormal vessels and glial tissue, ROP can lead to blindness through scarring and tractional retinal detachment. In such rare advanced untreated cases, ROP can be the cause of leukocoria in smaller eyes. The growing incidence of this condition parallels the improving survival rate for low-birth-weight infants. Eighty percent of cases of ROP resolve alone. New, early, aggressive detection and treatment protocols are designed to prevent scarring and preserve vision.

Rhabdomyosarcoma

A very aggressive malignancy of embryonal muscle tissue found in the orbit. It must be differentiated from orbital cellulitis (see earlier definition). Rhabdomyosarcoma manifests as an acute red swollen eye. It is curable with irradiation and chemotherapy, which preserve vision in 80% of cases.

Strabismus

Any deviation of the eyes away from their common alignment toward the object of regard. The misalignment can be horizontal, vertical, or torsional. A comitant strabismus measures the same in all positions of gaze and normally excludes a paralytic or myogenic cause for the deviation.

TORSCH lesions (ocular)

TORSCH is an acronym for congenital toxoplasmosis, rubella, syphilis, cytomegalovirus, and herpes simplex. These syndromes include cataract (leukocoria) and abnormal retina.

Toxocara canis

Larvae of the canine Ascarididae, which may be picked up by children from dog feces and dirt, may cause major ocular disease. The ocular involvement often is asymptomatic, being detected as a leukocoria. Mostly 3- to 5-year-olds are affected. Blindness (in one eye only) may be caused by retinal traction secondary to the scarring induced by the dead larvae lodged in the posterior uvea. The vitreous inflammation, followed by retinal detachment, causes the appearance of leukocoria. Only very early treatment with systemic steroids may offer potential benefit.

Uveitis

Inflammation of the uvea. In children, uveitis often occurs in persons with the monoarticular or pauciarticular forms of chronic rheumatoid arthritis(a term now more frequently used in pediatric practice than juvenile rheumatoid arthritis.) It occurs most often in girls 4 to 6 years of age who test seronegative for rheumatoid factor, seropositive for antinuclear antibody, and seronegative for human leukocyte antigen B27. The inflammation is usually chronic, indolent, and bilateral. Blindness may occur because of cataracts, glaucoma, or corneal disease. The eye stays white, without redness, until the end stage of the disease. The only possible clinical screening that can be performed between slit-lamp examinations involves a pupillary examination that can be taught to the parents (Fig. 8-7). The examination is difficult in dark-eyed persons but can be enhanced by dilating the pupils (during a lively conversation at the supper table or by pharmacologic means at the physician’s office).

FIGURE 8-7 A, Pupillary anomalies in chronic uveitis of juvenile idiopathic arthritis. They are caused by inflammatory adhesions (synechiae) between the iris and the lens. B, The anomalies are best seen when the pupil is dilated.

Obtaining the History

Obtaining the child’s cooperation is so critical for evaluation of the visual system that it is sometimes useful to postpone most of the history-taking until after the eye examination. Your initial efforts should succeed in getting the youngster interested in new visual toys and games that you will be introducing during brief playful moments. As you examine the child, elicit details from the parents about the relevant background issues—family history, pregnancy, perinatal events, and developmental milestones. Also elicit general impressions from the parents about the child’s visual abilities. Other history details that will be needed depend on the initial complaint and your findings.

Approach to the Physical Examination

General observation

In ophthalmology more than in any other specialty, observation is the most important technique to master; let the child show you the nature of the problem. It may seem impossible to evaluate a child’s visual system when you are faced with a pair of tightly closed eyelids, but often, you can achieve success only by resisting the temptation to touch, probe, or test.

Key Point

Your face is the most available and reliable target to confirm some form of vision in children.

Behavior

• Does the child walk in the examination area or run into things, or is the child wheelchair bound?

• Do you observe any eye gouging or poking (a form of mechanical retinal self-stimulation characteristic of blind children)?

Head Position

• Is the youngster’s head held straight up or down? There is no advantage to the child in holding the head up when he or she has no vision. Also, photophobic children avoid the light by hiding from it, holding their heads down.

• While looking at a visually demanding target such as a small picture, does the child’s head turn sideways to prevent diplopia (double vision) because of an extraocular muscle paresis or to stabilize the eyes (nystagmus)?

• Does the head tilt to alleviate diplopia, as in superior oblique weakness, or seem to fall forward (chin down) or backward (chin up), as in certain types of strabismus, or to see better from under a droopy lid?

Facial Features

• Is the child’s face symmetric and normal-looking or dysmorphic, suggesting the possibility of a syndrome?

• Does the child’s nose appear wide at the base (because of epicanthal folds), giving the impression that the eyes are turned in, especially when the child looks sideways?

Ocular observations

Open Versus Closed Eyes

• Are the child’s eyes open, or are they closed because of photophobia (the inability to tolerate normal daylight)?

• Does only one eye close in bright light or while outdoors because of an outward turn (exotropia)? To get a sleepy baby to open the eyes spontaneously indoors, gently blow air in the baby’s face or tickle a foot. If these techniques fail, hold the baby and perform a few rotations in either direction to stimulate oculovestibular responses (see the discussion later in this chapter for details of the spinning technique).

• Does the child have droopy lids or obvious bulging of the tissues over and around the eyes?

• Are the lids moving up and down during feeding, as in the Marcus Gunn oculotrigeminal dyskinesia?

Tearing Eyes

• Are the tears clear, or are they replaced by thick discharge (indicating infection)?

• Does the child have photophobia (indicating corneal disease or congenital glaucoma)?

Red Eyes

• Is the redness more pronounced in the cul-de-sac and at the lid margin, as in persons with blepharoconjunctivitis?

• Alternately, is the eye pink all over, as in viral conjunctivitis?

• Is the redness more intense around the cornea where it meets the sclera (limbus), as in persons with corneal diseases and intraocular inflammations (Fig. 8-8)?

• Is there a preauricular node, a sign of a lymphadenopathy associated with a conjunctival infection?

FIGURE 8-8 Distribution of maximum redness in three common causes of red or pink eye. A, Margin of the lower lid with inferior conjunctiva in blepharoconjunctivitis (often caused by Staphylococcus). B, Overall redness, the classic viral pink eye (often caused by an adenovirus). C, Limbal or circumcorneal redness, the so-called ciliary flush of corneal or intraocular inflammation (typically observed in persons with corneal erosions or ulcers, or in persons with acute anterior uveitis, which is rarely seen in children).

Bigger-Than-Normal Eyes

Eyes appear larger than normal in persons with congenital glaucoma (the cornea is bigger). A baby’s cornea should not appear to be bigger than that of an adult. To help make the comparison, have an adult hold the baby sitting forward on his or her lap, with both facing you. Have them put their faces close to each other so that the two pairs of eyes are in proximity. Comparison is easy with mothers and babies in a cheek-to-cheek position or with the baby’s head just below one parent’s chin (Fig. 8-9).

FIGURE 8-9 Assessment of corneal diameter. The child’s corneal size is compared with the mother’s.

Cloudy Eyes

The cornea may be cloudy in persons with congenital glaucoma, congenital corneal malformations, or rare storage diseases (e.g., mucopolysaccharidoses).

Jittery Eyes

Nystagmus (i.e., jiggling, wiggling, trembling, or instability of the eyes) can be caused by intracranial tumors, cataracts, or retinal diseases, or it may be idiopathic and purely motor.

Protruding Eyes

Proptosis is rarely equal in both eyes. By looking from above the child’s forehead, you can confirm your suspicion of a true proptosis. Exophthalmos (its other name) is often an ominous sign of either severe infection, neoplasm, or severe malformation in the orbital region.

Demonstrating Corneal Light Reflexes

A normal shiny cornea shows a neat, crisp light reflection when a light source is aimed at it. You can see the reflection almost in the center of the child’s pupils when both eyes are looking at the same light source, held between you and the child at 25 cm. If the corneal light reflexes are not positioned symmetrically, assume that both eyes are not looking at the light (Fig. 8-10). Judging the position of the light reflexes requires practice; the reflex is neither highly specific nor terribly sensitive for detecting slight degrees of eye misalignment (strabismus), but it is a good start.

FIGURE 8-10 Corneal light reflexes in esotropia (A), exotropia (B), and hypertropia (C).

It also is useful to show parents what a pseudostrabismus really is: a common pediatric nondisease that often concerns parents and physicians unnecessarily. It is usually seen in younger children with broad, flat nasal bridges and epicanthic folds. When the child looks to one side or the other, the eye turned toward the nose becomes partly hidden under the epicanthic fold, creating a false impression of strabismus—an optical illusion (Fig. 8-11 and Plate 8–11). The eyes look turned-in because of the asymmetry of scleral show. You can show the true alignment with the corneal light reflexes. The corneal light reflexes can be evaluated quickly with the ophthalmoscope at the same time as the pupillary red reflexes (described later in this chapter), but an otoscope light is a better choice for a more careful evaluation of a deviation.

FIGURE 8-11 Comparison of the corneal light reflexes in a person with esotropia (A) and epicanthal folds (so-called pseudostrabismus) (B).

If you establish that a true strabismus exists, it is not worthwhile to try to determine how large or small it is. The strong suspicion of genuine strabismus is what counts. Evaluate whether the angle of strabismus (the asymmetry between the corneal reflexes) is the same in different fields of gaze as you observe the child while he or she is looking around the room. This determination will indicate whether the strabismus is comitant or incomitant. If one or more extraocular muscles do not work properly (whatever the cause), the degree of strabismus varies with the direction of gaze; this phenomenon is called incomitance. Unlike a comitant strabismus, an incomitant strabismus has serious implications until proven otherwise.

Demonstrating Pupillary Red Reflexes

Take the few seconds required to verify the presence of a pupillary red reflex in each eye for every young patient, whether or not the youngster has an eye problem. Evaluating the quality and symmetry of the pupillary red reflections, known as the Brückner test, is universally considered a valid screening method for detecting visual anomalies in children 6 months of age and older.

Remember those Halloween party color photographs taken with a cheap flash camera, in which everyone looks at the camera flash and appears to have big red eyes? Look for the same effect when examining infants and children for the red reflex (Plate 8–12). Demonstration of the red reflexes requires the following conditions and instruments:

1. A room darkened slightly to dilate the child’s pupils and enhance the red reflexes

2. A light source aimed at the examined eyes that allows you to visualize its reflection from the fundus (i.e., a direct ophthalmoscope)

3. Absence of optical obstructions between you and the child’s choroid (behind the normal retina)

4. A child with normal eyes

Set your direct ophthalmoscope at the widest beam setting. Turn the wheel until you see the patient’s eyes clearly, staying about 2 feet (60 cm) away from the child to prevent both unexpected uncooperative behaviors and accommodative pupillary constriction. Aim the beam so that it illuminates both pupils, and observe (Fig. 8-12). The first observation should confirm normal or abnormal corneal light reflexes. In newborns, this may be the only chance to combine observations of corneal and pupillary light reflexes, at least in the primary position (i.e., eyes looking straight ahead).

FIGURE 8-12 How to elicit the pupillary red reflexes. Make sure the child is comfortable in his or her own environment (with his or her own things). Position yourself about 2 feet (0.61 m) away, with the widest beam of the ophthalmoscope encompassing both pupils. Rotate the lenses of the instrument until the child’s eyes are in focus. You can assess the corneal and the pupillary red reflexes at the same occasion (Brückner test). Looking just above the ophthalmoscope sometimes enables you to see the corneal light reflexes more clearly.

In white persons, the pupillary red reflexes should be orange and equally bright. In more darkly pigmented persons, including Native Americans and some Asians, the orange color is less bright. Anything else is abnormal.

Abnormal red reflexes could be caused by problems such as an opacified cornea (as in Hurler syndrome, a mucopolysaccharidosis); cataract (opacity of the lens); or retinoblastoma, a potentially lethal retinal malignancy. Mild asymmetry of brightness between the reflexes is produced by large refractive errors and by various degrees of strabismus. Normal red reflexes are shown in Plate 8–11.

Knowing how to assess the pupillary red reflexes (and remembering to do it) can sometimes mean the difference between life and death for your young patient.

Specific Examination Techniques

Additional specific techniques that can help establish a reasonable diagnosis are described in the following sections.

Testing visual acuity

Face Follow Test

From birth onward, infants prefer looking at the human face to looking at other objects. Take advantage of this preference when you want a child to look at something. Remember the following points:

1. A child who looks at you can see you.

2. To the child 6 months of age or older, the contrast of white teeth surrounded by darker lips adds a compelling detail to the face as a preferred visual target.

3. Conversely, wearing glasses can interfere with the face follow test, so take off your glasses and remember to smile!

Testing for Optokinetic Nystagmus

Optokinetic nystagmus (OKN) describes the eye movements produced when a succession of relatively slow-moving targets, maneuvered in the same direction over a short time, is presented to the child. The eye movements have (1) a slow phase, corresponding to pursuit of a target, followed immediately by (2) a quick, jerky fast movement (saccade) that rapidly returns the eyes to a subsequent target as it appears in a more central part of the visual field after the preceding target has moved away. This cycle repeats continually as long as sequential targets are presented.

Elicit OKN in newborns or young infants by showing a series of black-and-white vertical stripes mounted on a slowly but steadily moving cloth. Be sure the newborn is awake and alert with the eyes open before you begin the test. For older children, replace the stripes with cartoon characters.

Key Point

If the child sees the OKN stripes, his or her eyes will move, which makes it a good vision test for youngsters who cannot or will not talk.

Simple black and white stripes work well, but red and white stripes work even better (Fig. 8-13). You also can use an inexpensive striped necktie.

FIGURE 8-13 Using optokinetic nystagmus in an infant to confirm the presence of some vision. A cloth featuring red and white bands (here, a hospital receiving blanket) is positioned 1 foot (30 cm) in front of the child and then moved sideways at a speed of about 1 foot per 2 seconds.

It is even possible to quantify vision with OKN using an array of OKN targets with stripes of different widths. Some early research on vision testing in nonverbal subjects was based on the principle that when the stripes are placed too close together, OKN stops.

Testing for Fixation Behavior

While the face follow and OKN tests are used mainly to assess visual capability, the central steady maintain fixation (CSMF) method is used to assess one eye at a time, hence to compare one eye with the other. Used routinely in infants with strabismus, this technique evaluates the fixation behavior pattern. Cover the child’s eye with a finger, the parent’s hand, or, if all else fails and you do not mind risking the loss of the child’s cooperation for the day, a patch (see the section on the cover test). Show the uncovered eye an interesting visual target and assess the response by answering the following questions:

1. Is fixation central—that is, does the eye appear lined up with the target?

2. Is fixation steady—that is, does the eye appear to be stable?

3. Is fixation maintained—that is, when the cover is taken away from the other eye, does the tested eye remain fixed on the target?

The last component, maintaining fixation, really compares the two eyes. If vision is better in the covered eye, it will pick up fixation vision preferentially when it is uncovered. The child is unlikely to maintain fixation with the weaker eye. Often, the poorer eye shows some unsteadiness or even some paracentral fixation. The child’s behavior also is different (see section on the cover test).

Testing Visual Acuity Using LH

LH, the standard test for visual acuity in children older than 41 months of age, derives its name from the inventor of the test, Dr. Lea Hyvarinen. Unlike the Snellen chart, the standard vision chart used for adults at the physician’s office, the LH test does not require the child to know how to read, which provides a definite advantage. The LH test also provides an advantage over the Illiterate E test in that it does not test the ability to differentiate between right and left. Indeed, the LH test optotypes are symmetric from left to right. In the Illiterate E vision chart, the letter E is presented in all four cardinal directions—up, down, left, and right—and the child signals the difference between left and right by pointing when giving the correct answer. This requirement greatly limits the reliability of the Illiterate E test in many children younger than 6 years.

In the LH test, the child is given a plastic board with four symbols on it and is simply asked to point out on the board the symbol shown by the examiner on a typical visual acuity–type card hung on the wall. It is performed at a distance of 10 feet (3 m) for better compliance in younger children. The test, which is widely available, has components that are standardized for the 3-m distance and are made of durable plastic. The test also has decreasing spaces between letters proportional with the decreasing letter size; this feature maintains the crowding aspect of the test, which is important in testing for amblyopia. Every clinic or office should have this test kit to measure vision (Fig. 8-14).

FIGURE 8-14 LH vision measurement. You can teach a 3-year-old the pointing game in less than a minute. Conduct the test with the child positioned at a distance of 10 feet (3 m) from the visual-acuity card designed for that distance and mounted on the wall. Point to a pictogram on the card, and ask the child to point out the same one on his or her board.

Key Point

Your face is an ideal fixation target for children of all ages. An OKN test of some sort is useful for nonverbal children or to prove the presence of vision (e.g., in the hysteric or malingering patient). CSMF fixation behavior compares the two eyes; the LH test is for children older than 3.5 years.

Common Questions Asked About Visual Acuity Assessment

A common question is whether each eye should be tested singly or both eyes should be tested at the same time. You should first allow children to use both eyes, because they become upset if they are not allowed to look at things with their good eye (see the sections on testing for fixation behavior and the cover test in this chapter). In testing both eyes at once, you may observe important phenomena, such as abnormal head positions, head movements, tearing, and blinking. Perform a quick check to confirm any suspicion of a bad eye. Assess the vision of the bad eye before testing the good one, making sure the occluded eye is well covered. Use an adhesive patch to prevent peeking.

Another common question is whether near vision should be tested. Because the reading cards are poorly standardized, leave this assessment for the adults who must be tested for presbyopia.

Assessing extraocular movements and looking for incomitance

Spinning

The vestibular system has a major influence on eye movements. Spinning a child stimulates the vestibular system, which in turn stimulates the extraocular muscles. This method is used mainly for testing infants. To do it effectively and to appreciate what is actually going on with the child’s eyes, you must hold the child up in the air, facing you and tipped slightly forward, with his or her head a few inches away from yours (Fig. 8-15); watch the child’s eyes as you turn yourself and the child around, first in one direction (two or three turns), then in the other direction. The baby’s eyes should deviate in the direction of the turn. With this technique, not only will the youngster open his or her eyes, but the horizontal deviation of the child’s eyes will allow you to assess simultaneously the medial (third cranial nerve) and lateral (sixth cranial nerve) rectus muscles of both eyes. One word of caution: Do not spin the child for too long. After a few seconds, the surprise that prompts the child’s eyes to open can change to unhappiness at being suspended in the middle of nowhere and spinning dangerously in the arms of a stranger.

FIGURE 8-15 Spinning the baby to evaluate extraocular motility. Note the 30-degree forward inclination of the baby’s head, which is performed to achieve maximum stimulation of the horizontal semicircular canals. This inclination ensures a good response of the horizontal recti. A half turn in each direction often is sufficient to generate good movement of the eyes.

The Frame

Have an older child follow an object of interest (e.g., a red nipple placed on top of an otoscope that has been turned on) to the four corners of an imaginary frame around the face. This technique tests all of the extraocular muscles (Fig. 8-16). You can readily detect any anomaly of ocular movement, especially if you observe the corneal light reflexes carefully.

FIGURE 8-16 The frame used to evaluate comitance of a strabismus. A slow continuous movement of the dim fixating light along an imaginary frame around the patient’s eyes allows the assessment of all 12 extra-ocular muscles. LIO, left inferior oblique; LIR, left inferior rectus; LLR; left lateral rectus; LMR, left medial rectus; LSO, left superior oblique; LSR, left superior rectus; PP, primary position; RIO, right inferior oblique; RIR, right inferior rectus; RLR, right lateral rectus; RMR, right medial rectus; RSO, right superior oblique; RSR, right superior rectus.

Twisting the Head

As a last resort, while the child looks at you, hold the top of his or her head and turn it quickly, first to one side and then the other (Fig. 8-17). This maneuver may upset the child a little, but it allows assessment, through the vestibular system, of the activity of the horizontal muscles. Perform this movement vertically to assess the vertical muscles (superior and inferior rectus muscles, innervated by the third cranial nerve).

FIGURE 8-17 A through C, Twisting the child’s head to evaluate horizontal ocular movements. This technique is used as a last-resort to find out whether an eye can adduct (i.e., turn toward the nose by the action of the medial rectus) or abduct (i.e., turn in the opposite direction by the action of the lateral rectus). Use a dimmed light source to assess the corneal light reflexes and as a fixation target. Both the fixation and the vestibular stimulation generated by actively moving the head help produce changes of position of the eyes as the head is rotated.

Key Point

Incomitant strabismus, which changes with different gazes, indicates an effector problem from the brain stem to the muscles. It is therefore a sign of significant disease.

Assessing visual fields

Assessing visual fields in children is not as daunting or difficult as it might seem. In most situations, you can tell the child to look for the wiggly fingers. Instead of asking a child to fix on a stationary target while you check the peripheral field, as is done with adults, ask the child to look for a more exciting target, as follows (Fig. 8-18):

1. Sit 2.5 feet (75 cm) in front of the child, with your eyes at the same level as the child’s.

2. Ask the child to look at your nose.

3. Now, extend both arms in opposite quadrants.

4. Wiggle two fingers on only one hand and ask the child to find the wiggly fingers. The child may just look at them or may even try to grab your hand.

5. Repeat step 4 with your other hand.

FIGURE 8-18 Testing visual fields. While the child looks at your face, ask him or her to tell you how many fingers you are holding up. Two opposite quadrants are assessed at the same time, one eye at a time. Make sure the child’s hand is well apposed to the nose to prevent peeking.

Two variations of this technique can be used, depending on the child’s age. If the child is too young to play the wiggly finger game, just watch the youngster’s eyes as you introduce into the peripheral fields either your hands (as just described) or an interesting target (a bright, small silent toy or a familiar face) from behind the child’s head. With an older child, do not wiggle your fingers; instead, present various combinations of numbers of extended fingers on both hands simultaneously and in opposite fields of each eye. Ask the youngster to tell you the total number of fingers shown or to count the fingers on each hand while he or she looks at your nose. Assessing two opposite quadrants at the same time enables you to examine all four quadrants of each eye very quickly.

Although these tests for visual field assessment are qualitative only, they can be very useful in many situations. For example, consider a young boy who keeps banging into things after sustaining a brain injury. Has he lost his balance, is he having absence seizures, is he careless because of some personality change, or does he have a recognizable visual field defect? Visual field assessment can help determine the cause of the behavior.

Cover test for strabismus and vision

With the child’s attention on an object placed nearby or on a person of interest placed straight ahead, look for shifts of the eyes as you cover one of them. Movement may occur only as you remove the cover or may be seen in only one eye. The responses depend on the vision of each eye and the cause of the strabismus. An observable shift occurring during the cover test should confirm the impression gained during examination of the corneal light reflexes. Sometimes, however, to confirm the parent’s observations, you must have the child fixate on a very distant object (e.g., through a window) to elicit a movement of the eyes with the cover test. This phenomenon is characteristic in persons with intermittent exotropia.

The cover test also can tell you something about vision (Fig. 8-19). If you try to cover the child’s only good eye, you will be informed of that fact in more than one way: The child either cries or becomes uncooperative, or you cannot keep the eye covered because the child’s eye, his or her whole head, or a hand moves to reestablish the vision you have just interrupted. The child will get both you and your cover out of the way. Unfortunately, such a response may spell an end to the child’s cooperation.

FIGURE 8-19 The cover test, which is used to compare vision between the two eyes. An infant with right esotropia may not resist having the cover placed over his deviated eye (A) but does protest the occlusion of the dominant eye (B). In this patient, poor vision of the right eye must be suspected, especially when the eye has unstable fixation.

(From Von Noorden GK, Maumenee AE: Atlas of strabismus, 4th ed, St Louis, Mosby, 1983, p 65.)

Ophthalmologists use the cover test regularly to measure the angle of strabismus. For the pediatric examination, it is sufficient to confirm the existence of a strabismus and to help compare the vision in the two eyes.

Funduscopy in children

Funduscopy should be reserved for the end of the examination, right before the child leaves the examining room, unless corneal staining is indicated (see the next section). Funduscopy is sometimes a frustrating experience for both the examiner and the child. If you really suspect an abnormality, dilate the pupil to see what you are looking for. Use a short-acting cycloplegic, such as tropicamide 1%, putting one drop in each eye. Pupillary dilation is achieved within at least 20 minutes in most children; it may take a little longer in children with darkly pigmented eyes. The easiest way to put drops in the eyes is to have the patient lie supine with the eyes closed. You then put the drop in the inner canthus (corner of the eye) and ask, or wait, for the child to open his or her eyes. Instantly, the drops are in, and nobody has had to fight—at least until the next time, when the child may remember your trick.

Most young children will not hold their eye still while you try to locate some familiar landmark, such as the disc or a blood vessel. The solution is for you to stay still, let the child’s eye do the moving, and let your eye do the looking. The chances of finding something are far better if you are not moving while you search. Because the other secret of funduscopic success is good old practice (for which there is no reasonable substitute), try to examine the fundi in most infants and children with each complete physical examination. Funduscopy will become progressively easier for you.

You should make the following three important observations as part of the funduscopy:

1. Evaluate whether the red pupillary reflex is equal in all four fundus quadrants. You can accomplish this goal without having to obtain a perfect focus on the retina; perform the examination at a distance of 25 cm (10 to 12 inches) from the child.

2. Once the fundus is in focus, make sure you can see a normal foveolar reflex. Invite the child to look at your little magic light. Sometimes the child’s curiosity prompts him or her to do this anyway when you come close with the direct ophthalmoscope. One problem is that shining the light on the fovea stimulates the pupillary light response maximally (constriction) and may make viewing of the fundus difficult. Do not despair: The sharp bright foveolar reflection of the ophthalmoscope is easy to see.

3. Visualize at least part of a well-demarcated temporal edge of the disc as it passes by.

An even, red pupil indicates an attached retina with no major inflammatory or tumor process. Good fixation plus a sharp foveolar reflex eliminates an organic cause of poor vision, especially if the optic nerve looks normal. Most optic nerve diseases in the child involve the temporal half early in their evolution.

Lacrimal sac examination

In cases of lacrimal duct obstruction, the most important way to eliminate recurrent infections (and, according to some persons, a good way to help spontaneous resolution of the problem) is to know how to empty the lacrimal sac of its mucopurulent secretions. The technique is simple and is actually the best way to examine the lacrimal system to confirm a blockage. Minimal knowledge of the anatomy is required: Simply palpate the bony depression behind the insertion of the inner canthal ligament on the medial orbital rim. The best place to start is on yourself, as follows:

1. Find the small, hard bump in the inner corner of your eye with the index finger of your hand on the same side.

2. Roll your finger posteriorly to feel a small depression where the end of a small cotton-tipped swab could fit.

The next step is to do the same in a normal newborn to realize the difference in size. Finally, try it in a patient with a presumed blocked tear duct (Fig. 8-20). You will discover that (1) it is difficult to feel the depression and (2) while you roll your finger, a significant amount of secretion will appear in the child’s eye.

FIGURE 8-20 A, Lacrimal sac drainage, recommended to be performed once a day, uses slow but firm pressure applied by rotating the finger posterior to the lacrimal crest. Parents should locate their own sac before trying the procedure on the child. B, Wrong way to drain the sac; the finger used (in this case, the index finger) is too big, the position of the finger is too anterior, and the pressure is applied to the side of the nose.

The latter finding is proof of a blocked tear duct, whereas the fullness of the tissues on palpation was the dilated lacrimal sac waiting to be drained. All you have to do now is to show the parents how to do the finger roll, which, by the way, is not a massage.

Corneal staining (for corneal injuries)

When indicated, you should attempt corneal staining before using cycloplegic drops to prepare for fundus examination. However, the procedural problems are twofold. First, the staining dye stings a bit, which could end the child’s previous amiability. Second, when fluorescein staining is indicated (e.g., as with corneal erosion or the presence of a foreign body), there is usually photophobia and discomfort, which may make it impossible to induce the child to open his or her eyelids.

Key Point

Forcing open the lids of any patient is risky because it is possible that a ruptured globe will empty its contents when the lids are pried open.

Figure 8-21 illustrates the procedure for corneal staining, in which a fluorescein paper strip, moistened with a couple of drops of artificial tears or normal saline solution, is applied at the lower lid margin of the open eye.

FIGURE 8-21 Application of a fluorescein strip. Warn the child first that you will be tickling the eyelashes. Instruct the child to look up, and just touch a wet paper strip of fluorescein to the edge of the lower lid. Immediately withdrawing the strip prevents an uncomfortable corneal touch when the child blinks. Use of a cobalt-blue light helps illuminate the pattern of a stained corneal epithelial defect.

Applying Sequential Logic to Assess Children’s Eyes

The following five different clinical situations illustrate how to apply sequential logical assessment to common specific visual problems. Table 8-2 lists the main examination techniques to be used in each age group. It is worth mentioning that these techniques also form the basis for the recommendations made by most pediatric professional groups in North America for vision and eye screening examinations in children.

Table 8-2 Main Examination Techniques by Age Group*

Case Histories

Case 1: Nystagmus

Nystagmus is frequently overlooked despite the fact that it is the most common presenting sign of debilitating, genetically determined ocular conditions. The presenting complaint is most often wiggly eyes (Fig. 8-22). See Table 8-3 for aspects to consider and questions to ask when a child has nystagmus. The first and most important question to answer is whether the child’s vision is good. If the vision is good, relax—the child most likely has idiopathic motor nystagmus, which is usually an early-onset hereditary condition (appearing at 3 months) with only moderate visual deficit.

FIGURE 8-22 Diagnostic algorithm for a child presenting with wiggly eyes. *Also called motor nystagmus.

Table 8-3 Nystagmus

Aspects to Be Considered	Questions to Ask Parents
Evidence of poor vision	Toys held close to face?
	Poor eye contact?
	Poor motor development?
Photophobia	Squinting outdoors?
	Opens eyes only in semidarkness?
	Stays up all night?
	Refuses to play outside?
Nyctalopia	Cries when lights are out?
	Runs into walls at night?
	Wets the bed?
Family history	Nystagmus?
Family history	Progressive blindness?

If the child’s vision is poor (found to be less than 6/30 [20/100], or evidenced by poor visual behavior), the underlying condition may carry a poor long-term visual prognosis with significant risk of recurrence in the family. Nystagmus, when accompanied by poor vision and photophobia, usually signifies some form of cone disease. Such conditions can be stable and are associated with very poor color vision. However, nystagmus plus night blindness (nyctalopia) probably indicates progressive retinitis pigmentosa. When neither photophobia nor nyctalopia is present in a child who has both nystagmus and poor vision, you should consider albinism, optic nerve disease, and severe idiopathic motor nystagmus as possibilities.

Key Point

In the child with nystagmus, a thorough pediatric ophthalmologic investigation is essential to establish the appropriate diagnosis, initiate genetic counseling, and provide appropriate support.

Case 2: Lid Ptosis

Lid ptosis (Fig. 8-23), which has important systemic and visual implications, is often poorly understood. Unilateral or asymmetric lid ptosis has greater clinical significance than bilateral ptosis. Systemic problems or other local lid abnormalities can be seen in persons with unilateral or intermittent ptosis. The child with ptosis often adopts a chin-up position, freeing the pupil to allow binocular vision.

FIGURE 8-23 Lid ptosis in a 1-month-old infant. The ptotic (droopy) lid completely obstructs the eye, making this condition an emergency. Failure to open the lid would result in a deep deprivation amblyopia of severity equal to or worse than that caused by a congenital cataract.

The presenting complaint is most often droopy lid, for which Figure 8-24 presents a diagnostic algorithm. Also see Table 8-4 for aspects to consider and questions to ask for a child with ptosis. The most important question is whether the ptosis is constant. If the ptosis is constant, involving one or both eyes, vision is at risk, and early intervention is required to allow normal visual development in the obstructed eye. This situation is comparable with that of the child with congenital cataract, in which severe visual deprivation prevents establishment of the normal neuronal organization of vision.

FIGURE 8-24 Diagnostic algorithm for a child presenting with a droopy lid.

Table 8-4 Ptosis

Aspects to Be Considered	Questions to Ask Parents
Hematoma	History of trauma?
Plexiform neurofibroma (see Fig. 8-6)	Birthmarks?
Plexiform neurofibroma (see Fig. 8-6)	Plexiform neurofibroma in the family?
Jaw-winking phenomenon (see Fig. 8-25)	Ptosis improves with drinking, sucking, and/or chewing?
Hemangioma (capillary) (see Plate 8–12)	Abnormal lid?
Hemangioma (capillary) (see Plate 8–12)	Bluer when crying?
Lymphangioma (see Fig. 8-4)	Increase in size with colds?
Lymphangioma (see Fig. 8-4)	Increase in size after trauma?
Third cranial nerve palsy (ophthalmoplegia)	Little voluntary eye movement of one eye?
Acquired third cranial nerve palsy	Diplopia when lid open?
Third cranial nerve palsy and aberrant regeneration	Lid movements with attempted eye movements?
Myasthenia gravis	Ptosis gets worse intermittently in the afternoon?
Myasthenia, mitochondrial diseases	Poor gag reflex and/or poor feeding?
Myasthenia, mitochondrial diseases	Progressive weakness during the day?

The lid’s appearance helps identify local tumors, such as hemangiomas, whereas a good neurologic examination, including assessment of ocular motility, often gives clues to rarer congenital misfirings, such as Marcus Gunn oculotrigeminal dyskinesia (jaw-winking phenomenon; Fig. 8-25), myasthenia gravis, and even mitochondrial diseases.

FIGURE 8-25 Jaw-winking phenomenon, or Marcus Gunn oculotrigeminal dyskinesia. The lid ptosis may be missed unless the jaw is made to move by sucking or chewing. The lateral movement of the mandible by the pterygoid muscle is accompanied by the elevation of the lid. In this case, when the jaw is moved to the left, the right lid goes up. This condition results from a congenital misfiring in the brain stem between motor cranial nerve V and cranial nerve III.

Always remember the possibility of deep amblyopia, even in cases of partial ptosis, because partial ptosis often is accompanied by a significant degree of astigmatism in the affected eye, which in turn usually causes amblyopia. Only prompt treatment, including surgery, can restore vision.

Case 3: Epiphora

Tearing, or epiphora, is the most common of ocular complaints, and the causes are innumerable, from a hysterical emotional reaction to a splash of a destructive alkali in the eyes. Figure 8-26 presents a diagnostic algorithm for a child presenting with tearing eyes. In young children, the differential diagnosis often is somewhere between a chronic conjunctivitis and the dreaded (albeit extremely rare) blinding infantile glaucoma or a potentially devastating herpes simplex keratitis.

FIGURE 8-26 Diagnostic algorithm for a child presenting with tearing eyes.

See Table 8-5 for aspects to consider and questions to ask for a child with epiphora. The most important question to ask is whether photophobia is present. Equally important is assessment of corneal size, which is accomplished by comparing the child’s cornea with those of the parent on whose lap the child is sitting (facing you). An adult cornea has a horizontal diameter of 12 mm; anything bigger in a child is abnormal. Therefore, if an infant presents with teary eyes, photophobia, and enlarged cornea, the diagnosis is almost certainly infantile glaucoma, a potentially blinding but treatable disease. The disease can be unilateral in the early stages (i.e., only one cornea is enlarged).

Table 8-5 Epiphora

Aspects to Be Considered	Questions to Ask Parents
Blocked tear ducts	Two eyes first, then one only?
Blocked tear ducts	Worse with colds?
Congenital glaucoma	Photophobia?
	Constant tearing?
	Big eyes?

A teary eye with photophobia and normal corneal size could be caused by a corneal erosion, a foreign body, or herpetic keratitis. Fluorescein staining of the cornea is absolutely essential to detect an erosion. If both eyes are involved, ask whether anyone might have thrown sand, dirt, or even lime at the child. Obviously, in cases involving lime, immediate copious and prolonged irrigation can save the child’s sight. The typical story in a child with herpes keratitis is that of a nonresponsive unilateral conjunctivitis and teary eye with photophobia that remains after more than 7 days of topical antibiotic treatment. A photophobic teary eye also can be a sign of uveitis, although most uveitic eyes in children are asymptomatic.

Key Point

The presence of both photophobia and tearing is a sign of serious eye disease, and the patient should be seen promptly by an ophthalmologist.

A teary eye that has been present since birth, without photophobia but with secretions causing sticky lids, is most often due to a congenitally blocked tear duct. Without recurrent significant conjunctivitis, this problem can be monitored until spontaneous resolution occurs, which happens in 90% of the children before 1 year of age. Daily drainage (once per day) of the lacrimal sac greatly reduces the rate of recurrent infections. Control of recurrent infections is important to prevent damage to the lacrimal drainage system. Antibiotics are rarely needed; when they are indicated, any of the broad-spectrum antibiotic eye ointments is adequate for a 5-day, three-times-a-day treatment regimen. If infection recurs often, surgery (probing) is indicated.

Case 4: Strabismus

Because it is so common, strabismus is probably the subject that is most extensively covered in texts on children’s eye problems.

Key Point

Strabismus can signal several serious conditions and is never outgrown.

Parents commonly complain that the child’s eyes “do not look straight.” Figure 8-27 presents a diagnostic algorithm for this situation. Also, see Table 8-6 for aspects to consider and questions to ask for a child with strabismus. Immediately decide whether the corneal light reflections are normal. If they are normal in the primary position (looking straight ahead), check whether they are normal in other positions of gaze. An incomitant strabismus, which may show only in certain positions of the eyes and may or may not be present in the primary position, must be identified promptly. The cause of strabismus may be paralytic, restrictive, myogenic, or mechanical.

FIGURE 8-27 Diagnostic algorithm for a child presenting with eyes that do not look straight.

Table 8-6 Strabismus

Aspects to Be Considered	Questions to Ask
Intermittent esotropia	Worse when looking up close?
Intermittent exotropia	Worse when looking outside?
Large exophoria or esophoria	Worse when tired?
Migrainous ophthalmoplegia (third or fourth cranial nerve palsy)	Onset after a bad headache?
Idiopathic sixth cranial nerve palsy	Onset after a cold?
Rare congenital sixth cranial nerve palsy	Onset at birth?
“Congenital esotropia” (early-onset infantile)	Onset at about 3 months of age?
Accommodative esotropia	Onset at about 3 years of age?
Intracranial process with sixth and fourth cranial nerve involvement	Accompanied with or preceded by a chronic headache?
Onset of deviation (according to parents)	Ask the child to show you what he or she sees (diplopia signifies neurologic cause)
Onset of deviation (according to parents)	Inspect the family photo album for corneal light reflexes and abnormal head posture

If the corneal light reflections are abnormal in the primary position, evaluate the comitance of the deviation and establish the alteration of deviation. Does the child alternate the eye with which he or she fixes the target? If a child presents with an alternating strabismus, chances are that his or her vision is equal in the two eyes. Evaluation of the strabismus may raise the suspicion of poor vision. Such a finding has great clinical importance and may lead to an etiologic diagnosis. For example, absence of a normal red reflex in the deviating eye can be a sign of a retinoblastoma or cataract.

Case 5: Leukocoria

Although strabismus is a common condition with potentially major systemic implications and with obvious direct effects on visual function, leukocoria is an uncommon but ominous sign. The presenting complaint is most often an eye(s) or pupil(s) that does not look right, for which Figure 8-28 presents a diagnostic algorithm.

FIGURE 8-28 Diagnostic algorithm for a child presenting with pupils that do not look right.

Key Point

When a child presents with a white pupil, immediately define the state of the pupillary light reflexes, deciding whether they are present at all in either eye and, if so, whether they are symmetric.

Absence of a pupillary light reflex is significant and can be caused by corneal or choroidal lesions or anything in between. A white or gray-white reflex, termed leukocoria, is caused by lesions dense and close enough to the crystalline lens to reflect most of the penetrating light. Cataracts and retinoblastoma are two classic examples. See Table 8-7 for aspects to consider and questions to ask for a child with leukocoria.

Table 8-7 Leukocoria

Aspects to Be Considered	Questions to Ask
Localized lesion of the posterior pole, retinoblastoma	Seen only at certain angle?
Retinoblastoma	Onset about 1½years old?
	Family history?
	Photos of the child with abnormal red reflex ?
Toxocara canis (visceral larva migrans), retinal toxoplasmosis	Family pet (puppy or kitten)
	Youngster likely to put dirt in his or her mouth (2-4 years)?
Big retinal or disk coloboma	Onset at birth or very soon after?
Sarcoid or Candida vitritis	Sick child?
Uveitis with cataract and glaucoma	Arthritis?
Cataract and/or retinal detachment	History of recent eye trauma?
Cataract alone	Photos of the child with abnormal red reflex?
	Maternal rubella?
	Child taking steroids?
	Trauma?
	Diabetes?
	Storage disease?
	Chromosome anomalies?
	Family history?
Retinopathy of prematurity	Prematurity with low birth weight and use of oxygen?