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 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 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 ... determine intraocular pressure in children, ophthalmologic consultation may be required if emergency medicine providers not have experience with this procedure Suggested Readings and Key References... 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... 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