OPHTHALMIC EMERGENCIES

DEBORAH SCHONFELD, MD, FRCPC AND ALEX V. LEVIN, MD, MHSc, FRCSC

GOALS OF EMERGENCY CARE

A wide variety of pediatric ocular complaints are first seen by the emergency room physician. A number of acute disorders such as ocular infections and exposures of a toxic nature require the immediate diagnostic workup and management that is best carried out in the emergency department (ED). While many problems can, and should be, managed by the ED physician alone, others may require immediate or expedited ophthalmologic evaluation. The ED physician must be capable of conducting an ophthalmic history and physical examination to accurately assess each ocular complaint. This chapter discusses the approach to ophthalmic emergencies commonly seen in the ED. Ocular trauma (including injuries to the globe, cornea, and eyelids) is discussed in Chapter 122 Ocular Trauma. The approach to several other common eye complaints is outlined in the related chapters mentioned below.

KEY POINTS

RELATED CHAPTERS

EXAMINATION

Many children regard eye examinations and eye drops with the same fear that they harbor for injections. Therefore, it is important to gather as much information as possible before touching the patient or instilling eye drops.

A detailed history can be a valuable tool in focusing the examination and making a diagnosis. Questions regarding unilaterality/bilaterality, acute/chronic onset of symptoms, and prior ophthalmic care are particularly helpful. For example, a patient may be known to have an eye with poor vision, or to have had one eye patched for a visual problem suggesting amblyopia. Conversely, a child may be unaware of having poor vision in one eye because the pediatric brain is able to suppress the blurred image and focus solely on the clear image, allowing the child to proceed with normal activity unaware of the unilateral visual deficit. Importantly, an unremarkable visual screening examination at school does not necessarily imply that the vision was normal because false-negative tests are well known to occur.

It is often useful to start with assessment of the extraocular muscle movements. This procedure is discussed in Chapter 23 Eye: Strabismus. By using a toy or another interesting hand-held object, the physician can entice the child to look in the direction in which the object is placed. Both eyes should move equally in all directions. The examiner should test upward and downward gaze as well as eye movements to the left and right.

The examiner can use the direct ophthalmoscope as a tool to accomplish several tasks without touching the child. The ophthalmoscope light may be useful as a fixation target in testing eye movements, to assess whether the eyes are aligned (Hirschberg light reflex test, see Chapter 23 Eye: Strabismus), to test for a red reflex (see Chapter 122 Ocular Trauma), and as a simple hand-held magnifier. While viewing through the ophthalmoscope, the focusing wheel can be dialed in the direction of the black or green numbers to allow the eyeball to come into focus regardless of the distance between the examiner and the patient.

Visual acuity testing is usually performed at a distance of 20 ft or 10 ft. Most standard wall charts are calibrated to be read at 20 ft. If space does not permit this distance to be used, the patient can be placed 10 ft from the chart and the results interpreted with an adjustment for this distance. For example, the line marked 20/60 on the chart (a line that a person with normal sight can see at 60 ft but a person with that visual acuity would need to stand at 20 ft to see) becomes a 20/30 line when tested at a distance of 10 ft. In some centers or with some vision charts, the metric system is used with 20 ft being equivalent to 6 m. As examples, vision of 20/20 is written as 6/6, 20/30 as 6/9, and 20/200 as 6/60.

Chart selection is important when trying to obtain an accurate visual acuity. Letter charts should be used only for patients who can clearly recognize the alphabet. If there is any question by parental report, a number or picture chart (Fig. 131.1) should be used. When using picture charts that have colored figures, the examiner should avoid using those figures that are yellow because the bright illumination of the ED lessens the contrast between these figures and the white chart background making recognition more difficult. The “tumbling E” chart is not recommended in young children as it may be too complex for their developmental level and requires some sense of handedness, which is not developed until an age when they should easily be able to perform the other tests. This chart is more useful for older non–English-speaking children. It is sometimes referred to as the “illiterate E” test.

FIGURE 131.1 Picture visual acuity chart.

A useful option for children who are not “in the mood” to verbalize their responses or are very shy is the use of matching acuity chart systems. The two most common are the Sheridan Gardiner (Keeler Instruments, Inc., Broomall, PA) and HOTV (Precision Vision, La Salle, IL). In both situations, the child is holding a card that has all of the letters that are on the posted or hand-held chart 10- or 20-ft away. The child need not know letters but can identify them as shapes. For example, the H can be called a little ladder and the O a circle. Instead of verbally responding, the child points to the matching shape (letter) on the card he/she or his/her parent is holding. When using any visual acuity chart, it is not necessary to start with the largest symbol and have the patient read every symbol on every line thereafter. Doing so risks losing the child’s attention. Rather, one can start with the 20/20 line and then go to larger lines if the child is having trouble. The child needs to recognize only a few letters on each line. Minor errors such as the substitution of the letter F for the letter P, or the letter C for the letter O, may be tolerated.

It is almost an instinct for young children to use their better eye and suppress the vision in their lesser eye. Therefore, children should not be allowed to cover their eye with their own hand because the small cracks between the fingers can actually allow vision out of the “covered” eye and even improve that vision by the pinhole effect (see Chapter 122 Ocular Trauma). Children may also look around commercially available occluders for the same reasons. Perhaps the best way to obstruct the vision in the eye not being tested is to use a broad piece of tape, ensuring the tape also covers the depression at the bridge of the nose (Fig. 131.2). To help ensure the patient is not “cheating,” the examiner should look back directly at the child while standing by the chart indicating the letters or pictures.

Any child who can read a chart but shows reduced visual acuity should be tested using a pinhole. If vision improves with a pinhole then the patient only needs glasses and there is no organic abnormality causing the blurred vision.

After external examination and visual acuity are completed, the examiner can then proceed with other procedures as indicated, such as upper lid eversion and dilating the pupil. These techniques, along with the proper methods of examining the retina and optic nerve using the direct ophthalmoscope, are discussed in Chapter 122 Ocular Trauma.

FIGURE 131.2 A broad piece of tape can be used to obstruct the vision of the eye not being tested. If the tape is not adherent to the bridge of the nose, the child can peek out by turning the face to the side (right frame).

FIGURE 131.3 Paper clips can be bent into a retractor to open the eyelids.

When the eyelids or periorbital tissue is edematous or the patient refuses to voluntarily open the eyelids, proper examination can be difficult. The techniques described in Chapter 122 Ocular Trauma for opening the traumatized eye may be useful. Commercially available speculums, when used in association with a topical anesthetic, are a painless and efficient way of opening the eyelids. If these are not available, a Desmarres retractor can be helpful to control the upper eyelid and can also be applied simultaneously to the lower eyelids. A similar device can be fashioned out of paper clips (Fig. 131.3). When using a paper clip, it is important to inspect it after bending. Some have a coating that may become fragmented, potentially causing particles that could be dispersed to the conjunctiva or cornea as tiny foreign bodies. In addition, the paper clip should be cleaned with an alcohol swab before starting, and should not be used on more than one patient.

In infants, the eyelids may be separated using cotton swabs. The swabs should be placed at the midbody of the upper and lower eyelids. As they are separated, pressure should be applied down against the eyelid and the swab should be rotated inward toward the eyelashes. This will keep the eyelids in place so they do not spontaneously evert and further obstruct the examiner’s view. The cotton swab technique should not be used in patients being evaluated for eye trauma because pressure on the eyeball from this technique could cause further injury (see Chapter 122 Ocular Trauma).

It may be necessary to instill certain eye drops to complete the eye examination (e.g., topical anesthetics, dilating drops). Instillation of eye drops can sometimes be difficult because of swollen eyelids or patient noncompliance. Ophthalmic solutions are designed for a one-drop dose. Drops are most efficiently delivered by pulling down the lower eyelid and placing the drop in the inferior fornix. In patients who are extremely resistant, forced eyelid opening is needed to expose just a small strip of palpebral conjunctiva. The eyeball itself does not need to be visualized. An alternative technique involves placing the eye drop in the sulcus between the medial canthus and the side of the bridge of the nose while the patient is in the supine position. Every child must eventually open his or her eyes and when this happens the eye drop will naturally flow onto the conjunctiva. Topical anesthetics may be necessary to complete some parts of the examination, especially in the patient with significant pain. Topical anesthetics should never be prescribed for outpatient use. These are strictly diagnostic agents. Prolonged use of topical anesthetics may result in corneal ulceration.

COMMON EYE EMERGENCIES

Periorbital and Orbital Cellulitis

CLINICAL PEARLS AND PITFALLS

• Periorbital and orbital cellulitis have different clinical implications and treatments

• Orbital cellulitis is a vision-threatening infection that is characterized by its clinical features (pain or limitation of eye movement, optic nerve involvement, and/or proptosis)

• Since distinguishing between periorbital and orbital involvement can be difficult based on clinical observations alone, imaging may play a critical role in the diagnosis

• Many cases of orbital cellulitis can be managed medically with intravenous (IV) antibiotics, whereas other may require surgical intervention

Current Evidence

The orbital septum is an extension of periosteum from the orbital bones that inserts into the tarsal plate of the upper and lower lid to form the anterior boundary of the orbital compartment. Periorbital (or preseptal) cellulitis refers to infections limited to the soft tissues anterior to the orbital septum. Disease processes posterior to the orbital septum involve the contents of the orbit (fat, nerves, and extraocular muscles) and cause orbital (or postseptal) cellulitis. Involvement of the orbit can threaten vision and potentially result in spread to the cavernous sinus and central nervous system (CNS).

Periorbital cellulitis often has a local cause such as eyelid trauma, insect bite, or contiguous spread of an infection, such as conjunctivitis (especially neonatal gonococcal conjunctivitis) or dacryocystitis. Less commonly, it may also arise from sinusitis or an upper respiratory tract infection (URI). Orbital cellulitis most commonly results from sinusitis, which is present in up to 98% of cases. Other causes include orbital trauma and surgery, and infections of the teeth, ear, or face. It should be noted that the maxillary and ethmoid sinuses, the most likely to be involved when mucociliary clearance is impaired by a URI, are present at birth, but continue to grow and undergo pneumatization during the first few years of life. Thus, sinusitis may be a less common cause of orbital cellulitis in very young children.

The leading bacterial organisms responsible for periorbital and orbital cellulitis are Staphylococcus aureus and streptococcal species. Since the introduction of the Haemophilus influenzae type b vaccine in 1985, the incidence of this pathogen as a cause has dropped substantially.

Goals of Treatment

Accurate identification of periorbital versus orbital cellulitis is essential to proper treatment and a good clinical outcome. Timely administration of appropriate antibiotics is critical in all cases. Prompt recognition of symptoms and appropriate use of imaging allows for early diagnosis of orbital cellulitis, a potentially vision- and life-threatening condition. Ophthalmology consultation is indicated in all cases of suspected or proven orbital cellulitis. Surgical intervention may be required.

FIGURE 131.4 Periorbital cellulitis in a child with eyelid swelling, erythema, and tenderness.

Clinical Considerations

Clinical Recognition. Both periorbital and orbital cellulitis are more often seen in children than adults. Both conditions commonly present with fever, and periorbital erythema and swelling (Fig. 131.4)

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