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The absence of itching and pain should raise suspicion for an infectious cause
of conjunctivitis. Infectious conjunctivitis may cause diffuse unilateral or bilateral
inflammation. The differentiation among bacterial, viral, chlamydial, and other
types of conjunctivitis is sometimes difficult (see Chapter 123 Ophthalmic
Emergencies ). Viral conjunctivitis is the leading cause of red eye in children,
with adenovirus as the most common organism. It is characterized by
conjunctival hyperemia, chemosis, and a watery discharge. One eye is usually
affected first, followed by the other eye a few days later. It is commonly
associated with upper respiratory tract infection. A palpable preauricular lymph
node strongly supports the diagnosis of viral conjunctivitis. It usually appears
within a few days of the onset of viral conjunctivitis, although it is not present in
all cases. Productive purulent discharge, matting of the lids on awakening, lack of
itching, and no history of conjunctivitis are particularly characteristic of bacterial
conjunctivitis. Patients with nasolacrimal duct obstruction can also present with
discharge; however, the conjunctiva is rarely inflamed (see Chapter 123
Ophthalmic Emergencies ).

FIGURE 27.6 Blepharitis. Note crusts and flakes at base of eyelashes.


FIGURE 27.7 Subconjunctival hemorrhage.

If the injection is localized, the examiner should consider a specific list of
diagnostic possibilities. Subconjunctival hemorrhage is characterized by
localized, sharply circumscribed acute redness ( Fig. 27.7 ). There is no pain,
visual disturbance, or discharge. It is uncommon in children who do not have a
history of a direct blow to the eye. Subconjunctival hemorrhage in a young child
should prompt consideration for a coagulopathy workup, or the possibility of
nonaccidental trauma or suffocation. Pertussis infection can result in 360-degree
unilateral or even bilateral prominent subconjunctival hemorrhage, which is not
expected to occur with other causes of cough. Conjunctival petechia can rarely be

seen after strong Valsalva but usually with additional petechia elsewhere on the
face. Herpes keratitis phlyctenule, episcleritis, and scleritis may present with
focal involvement, as previously discussed. Localized injection of the conjunctiva
may be an indicator of an embedded foreign body, varicella, or other focal
processes that require an ophthalmologic consultation.
Acute acquired glaucoma causes a painful red eye, sometimes associated with
corneal clouding and decreased visual acuity. Acquired glaucoma, is most often
associated with trauma, other anatomic abnormalities, or iritis that would be
apparent on examination. Because it is difficult to determine intraocular pressure
in children, ophthalmologic consultation may be required if emergency medicine
providers do not have experience with this procedure.


Suggested Readings and Key References
Azari AA, Barney NP. Conjunctivitis: a systematic review of diagnosis and
treatment. JAMA 2013;310:1721–1729.
Bagheri N, Wajda BN, Calvo CM, eds. Wills Eye Manual, The Office and
Emergency Room Diagnosis and Treatment of Eye Disease . 7th ed.
Philadelphia, PA: Lippincott Williams & Wilkins; 2017.
Mahmood AR, Narang AT. Diagnosis and management of the acute red eye.
Emerg Med Clin North Am 2008;26:35–55.
Narayana S, McGee S. Bedside diagnosis of the ‘Red Eye’: a systemic review.
Am J Med 2015;128;1220–1224.
Wong MM, Anninger W. The pediatric red eye. Pediatr Clin North Am
2014;61:591–606.


CHAPTER 28 ■ EYE: STRABISMUS
MICHAEL P. GOLDMAN, BRUCE M. SCHNALL

INTRODUCTION
Strabismus refers to any misalignment of the eyes such that they are not viewing
in the same direction. If the misalignment occurs using binocular vision (i.e., both
eyes are uncovered), it is termed a tropia (e.g., esotropia), or manifest strabismus.
If it occurs only when the two eyes are no longer looking at the same object, it is
termed a phoria (e.g., esophoria), or latent strabismus. Esotropia (or esophoria)
refers to eyes that are turned in (cross eyed). Exotropia (or exophoria) refers to
eyes that are turned out (wall eyed). The terms hypertropia and hypotropia refer
to a higher or lower eye, respectively.
All children with strabismus require an urgent formal evaluation by an
ophthalmologist for definitive diagnosis and management, but the emergency
physician should attempt to answer two questions: (1) “Is this strabismus an
emergency?” and, if so, (2) “What is the most likely cause?”

PATHOPHYSIOLOGY
Six muscles surround each eyeball ( Fig. 28.1 ). Understanding the action of these
muscles allows for the definition of diagnostic positions of gaze ( Table 28.1 ).
This can be helpful in pinpointing specific muscle dysfunction. For example, if a
muscle that primarily governs abduction (e.g., lateral rectus) is impaired, the eye
is unable to abduct and will usually lie in a position of adduction (esotropia).
Likewise, if a muscle that is involved with downward gaze (e.g., inferior rectus)
is impaired, the eye will have a tendency to remain in relative upward gaze
(ipsilateral hypertropia).
In broad terms, strabismus is categorized into misalignment as a result of
impaired muscle function or misalignment in the presence of normal muscle
function. In general, there are only two emergent reasons why the function of a
particular muscle might be impaired: neurogenic palsy or muscle restriction.

Nerve Palsies
Three cranial nerves are responsible for the innervation of the six extraocular

muscles ( Table 28.1 ). The sixth cranial nerve innervates the ipsilateral lateral
rectus muscle. This nerve exits the ventral pons and then travels on the wall of the
middle cranial fossa (clivus), reaching the sphenoid ridge, along which it travels
until entering the cavernous sinus. The course of this nerve allows it to be injured