.A. Figure 74-2. Eva l uating the cornea l surface using a

narrow beam at a 45-degree angle. The curved beam

represents the reflection of l ight off the cornea . When

the cornea is in focus, protein deposits are freq uently

visual ized on its surface.

of fluorescein uptake (green fluorescence) that suggest corneal or conjunctival epithelial injury. Running or oozing of

the fluorescein (Seidel sign) is caused by aqueous humor

leaking from a full-thickness penetration of the cornea.

Evaluating the anterior chamber for cell and flare is the

third part of the examination. The slit height should be

decreased and the slit width increased to create a short,

wide beam of white light. Swing the light source temporally, aiming the beam of light nasally through the anterior

CHAPTER 74

.&. Figure 74-3. The appearance of the light when

eva l uating for cell and flare.

chamber at the height of the pupil (Figure 74-3 ). Push the

microscope forward until the patient's iris is in sharp

focus, then move back slightly until the iris is out of

focus-but not so far that the cornea comes into focus.

The focal plane is now between the iris and cornea, in the

anterior chamber. Using the pupil as a dark backdrop,

watch for any material reflecting the light. Flare is caused

by protein in the anterior chamber and creates a smoky

appearance in the beam of light (a common analogy is

"headlights in fog:') Cells will look like "dust particles in a

sunbeam." The presence of either signifies inflammation

of the anterior chamber. Use of dilating drops can cause

cells to be present and applanation tonometry can cause

flare, so slit lamp examination should be performed

before these other tests.

If a foreign body (FB) is identified during the examination, first attempt to wash it out using saline. If this is not

successful, it can be removed using a burr drill or a 25- or

27 -gauge needle. Anesthetize the patient's eye using proparacaine or tetracaine. Be sure the patient's head is stabilized by full contact with the forehead brace and chin rest.

Stabilize your hand on the patient's cheek or forehead so

the removal device will track any movements the patient

may make. Keep the removal device tangent to the surface

of the patient's cornea. Guide it to the cornea under direct

vision, switching to the eyepieces once the removal device

is in view. If using a burr drill, press the side of the burr

against the FB. When activated, the drill will "fling" the FB

out of the cornea. If using a needle, place it on a small

syringe (eg, insulin syringe) to provide better control.

Guide the needle to the FB and use a scooping or flicking

motion to pull the FB out of the cornea. Always move

tangential to the globe.

COMPLICATIONS

When using the slit lamp and syringe/needle to remove an

FB, careless attempts at removal or patient movement may

result in penetration through the cornea. Additionally, in

the setting of ocular trauma, avoid placing pressure on the

eye when the possibility of a globe rupture exists. Excessive

pressure may cause the intraocular contents to be extruded.

Suggested Reading

Knoop K, Dennis W, Hedges ]. Ophthalmologic procedures. In:

Roberts ]R, Hedges JR Roberts: Clinical Procedures in Emergency

Medicine. 5th ed. St. Louis, MO: Saunders, 2009, pp. l l4 1-l l 77.

Walker RA, Adhikari S. Eye emergencies. In: Tintinalli JE,

Stapczynski JS, Ma OJ, Cline DM, Cydulka RK, Meckler GD.

Tintinalli's Emergency Medicine: A Comprehensive Study Guide.

7th ed. New York, NY: McGraw-Hill, 201 1, pp. 1517-1 549.

Red Eye

Craig H uston, MD

Key Points

• Always begin with visual acuity, the vital sign of the eye.

• The patient should be instructed to remove contact lens and

not to put them back in until the symptoms have resolved.

• The presence of pain and the relief of pain with insti llation of anesthetic agents are helpful in determining the

cause of red eye.

INTRODUCTION

Eye complaints account for 3% of all emergency department (ED) visits. Red eye is a common complaint, and

although most cases are benign, self-limited conditions,

some may be vision-threatening. Conjunctivitis is the most

common cause of a red eye, but other frequent problems

include subconjunctival hemorrhage, corneal injuries

(abrasions, keratitis, and foreign bodies), and acute uveitis.

Conjunctivitis may be viral, bacterial, or allergic. Viruses

are the most frequent cause, especially adenovirus. The most

common bacterial pathogens are Staphylococcus aureus,

Streptococcus pneumoniae, and Haemophilus influenzae.

Chlamydia trachomatis or Neisseria gonorrhea are unusual,

butimportantcauses of conjunctivitis. Allergic conjunctivitis

is due to recurrent seasonal inflammation from allergen

exposure. About 15% of the population will experience

allergic conjunctivitis at one time in their life.

Subconjunctival hemorrhage is blood between the

conjunctiva and sclera that results from a ruptured con ­

junctival blood vessel. Subconjunctival hemorrhage is

caused by direct trauma or indirect injury. Although it may

be alarming to the patient, it is usually a benign process

that occurs with a sudden increase in pressure from sneez ­

ing, coughing, straining, or vomiting. If atraumatic, the

etiology is usually hypertension or spontaneous rupture.

• Follow a systematic approach to the physical examination:

visua l acuity, lids and lashes, conjunctiva, sclera, cornea,

pupil examination, and anterior chamber.

• Never prescribe topical steroids without consulting with

an ophthalmologist.

Corneal injury is common because the epithelium is

thin and easily damaged. Corneal abrasions are particularly

common, representing 10% of all ED visits for eye complaints. The cornea is resistant to infection, but when

injured, a potential portal to bacteria is created. Viral infections that cause injury to the cornea include herpes simplex

and varicella (ie, herpes zoster ophthalmicus). Contact lens

use may predispose the patient to keratitis or a corneal ulcer

due to gram-negative bacteria.