Indications

Visual acuity should be assessed as soon as practicable and before the patient is examined with bright lights. In the event of blepharospasm from an injury (e.g., abrasion, chemical exposure), a topical anesthetic may facilitate the examination. Patients are often encountered in the context of an eye complaint and say that they “can’t see.” In these instances, emergency visual acuity assessment should be performed first, beginning with evaluation of light perception, then hand motion, and finally counting fingers at 3 ft (Fig. 62-1). If the patient succeeds in performing these assessments, a near vision card may then be used or distant visual acuity assessed. In emergency circumstances, detailed formal vision testing is not essential; however, some form of visual acuity assessment is needed. In this situation, the ability to count fingers or read newsprint gives some indication of gross visual function. Formal visual acuity testing should never delay important therapeutic interventions such as eye irrigation.¹

Distant Visual Acuity Procedure

For formal vision testing, ask the patient to face a well-lit standard Snellen or similar eye chart from a premeasured distance of 20 ft. Use a card or the palm of the hand to occlude one eye at a time. If possible, examine all patients while wearing their current lens correction to obtain the best corrected distant visual acuity. If not available, measure visual acuity first without correction and then with a pinhole device, and note any improvement in visual acuity. This device functions as a corrective lens by reducing corneal refractive error. In general, visual acuity is improved with the pinhole device. Decreased visual acuity that is not improved with this device suggests that corneal refractive error is not the cause. Construct a pinhole device by punching one to several holes in the center of a card (3- × 5-inch index card) with an 18-gauge needle. Devices with one or more pinholes drilled into an eye cover are available commercially (Fig. 62-2A and B) or can be constructed from readily available material in the ED, such as the index card with holes just mentioned. Figure 62-2C presents a chart for testing visual acuity while the patient is on a stretcher or in a chair. The chart can be used directly from this text if held 14 inches from the eye. Begin by testing the affected eye or the one presumed to have the worst visual acuity. First, instruct the patient to read the smallest letters on the chart that can easily be seen. Then ask the patient to read letters that can just barely be made out (i.e., they do not have to be clear). If the patient is unable to read the largest letter on the chart, move the patient to half the distance from the chart (10 ft), or if using the figure in this text, move it 7 inches closer to the eye and repeat the procedure. Record the results reflecting the change in distance (e.g., 10/200). The numerator in the vision ratio is the distance of the patient from the chart and the denominator is the distance at which a patient with normal vision can read the line of letters. For patients who still cannot read the letters on the chart, test vision progressively as follows: the ability to count fingers, detect hand motion, and perceive light (with or without projection—the ability to perceive the direction of light), and finally, the inability to perceive light.²

Near Visual Acuity Procedure

Perform near visual acuity assessment in the ED at the bedside or at triage. Hold a pocket near vision card (see Fig. 62-2C) or any printed material in good light at a distance of approximately 14 inches in front of the patient and occlude each eye alternately as described earlier. When using available printed material in lieu of a near vision card, measure the size of the letters that are discerned by the patient. At a later time compare these letters with the size of the letters on the near vision card to deduce the patient’s actual visual acuity. When near vision is decreased, it is usually caused by either loss of visual function or poor accommodation as a result of advancing age (presbyopia). Less commonly, it is caused by traumatic mydriasis. Thus, examine patients with presbyopia with their reading correction in place to obtain the best corrected near visual acuity.

For patients who cannot communicate or in whom factitious blindness or malingering is suspected, check for optokinetic nystagmus (OKN) to determine whether the visual pathway is intact. To test for OKN, pass a regularly sequenced pattern in front of the eyes. If an optokinetic drum is available, rotate the drum in front of the patient (Fig. 62-3). This is not available in many EDs, however. In place of the drum, substitute a printed piece of paper such as newsprint (without photographs or large areas with no print) or a standard tape measure. Pass it in front of the patient’s eye at reading distance while instructing the patient to look at it as it moves rapidly by. Evaluate for tracking as demonstrated by nystagmus-like eye movements seen when the test object is moved from side to side in front of the patient. Such movement indicates an intact visual pathway. Finally, another effective method is to hold a mirror in front of the patient and slowly rotate the mirror to either side of the patient. Patients with an intact visual pathway will maintain eye contact with themselves as demonstrated by eye movement as the mirror is moved. A large mirror that reflects the patient’s entire face is most effective for this purpose.

All patients with decreased visual acuity from baseline require routine referral for further ophthalmologic follow-up; however, patients with moderately or severely decreased visual acuity not explained by refractive error require ophthalmologic consultation in the ED.

Indications and Contraindications

There are several diagnostic and therapeutic indications for dilating the pupil. Dilation is indicated for diagnosis when the fundus cannot be examined adequately through an undilated pupil. An elderly patient with miotic pupils and cataracts is an example of a patient in whom dilation may facilitate funduscopic examination. Dilation is therapeutically useful for many ophthalmic conditions, including inflammation of the eye. In the emergency setting, corneal injury with secondary traumatic iritis is a common example. Dilation helps the inflamed eye in two ways. First, it may hinder adhesions (synechiae) from forming between the iris and other ocular structures. Such adhesions eventually limit movement of the pupil and may precipitate glaucoma. Second, cycloplegic dilating agents relax the ciliary muscle spasm that often accompanies an inflamed eye and thus may reduce the pain associated with inflammation. Though traditionally used for these purposes, both benefits are largely theoretical with little formal evidence to support or refute their use in the ED.

Dilation is discouraged in patients with head injury who are at risk for herniation when it is necessary to monitor pupil findings. Dilation is contraindicated in the presence of narrow anterior chamber angles. Patients predisposed to having narrow angles may be unaware of this condition. Evaluate the depth of the anterior chamber before this procedure, and do not dilate the eye if there is any question of a narrow angle. To estimate the depth of the anterior chamber, shine a penlight tangentially from the lateral side of the eye. When the depth of the anterior chamber is normal, uniform illumination of the iris is seen. However, when the iris has a forward convexity as in the case of a narrow anterior chamber, only a sector of iris is illuminated and there will be a shadow on the medial (nasal) side of the iris (Fig. 62-4). With a slit lamp, the depth of the anterior chamber angle can be assessed directly. The definitive test for assessing the anterior chamber angle is gonioscopy, in which the anterior chamber angle structures are viewed directly by means of a special mirrored contact lens and a slit lamp. Gonioscopy is not a technique normally performed by emergency clinicians.

Systemic effects can develop after the application of eyedrops.4–10 Review the following sections on agents and complications before using these drugs in patients with compromised cardiovascular function.

Agents

Only two dilating agents are really needed in the ED. Phenylephrine (Neo-Synephrine) 2.5%, a potent sympathomimetic, is used for diagnostic dilation of the pupil and visualization of the fundus. The drug is short acting, and because accommodation is not affected, the patient’s vision is not altered. Phenylephrine 10% should not be used routinely because it can be absorbed systemically and, in rare cases, has caused hypertensive crisis, myocardial infarction, and death.8,9

For therapeutic cycloplegia in patients with iritis, 5% homatropine works well. Even though Table 62-1 indicates a maximum duration of 3 days, 24 hours is more common. Therefore, 5% homatropine is a useful therapeutic agent for traumatic iritis. Atropine should not be used for traumatic iritis because the undesirable effects of pupillary dilation and blurred vision persist for a week or longer after the associated corneal abrasions have healed. Atropine drops may be prescribed as part of the therapy for nontraumatic iritis after appropriate ophthalmologic consultation. Individuals with lightly pigmented irides tend to have greater sensitivity to cycloplegic agents than do individuals with greater pigmentation; the cycloplegic effect might therefore be more prolonged in people with light eyes. It might be difficult to dilate some patients with deeply pigmented irides, however, and numerous applications of drops might be required.

Malingerers may use mydriatic agents to dilate a pupil unilaterally for the purpose of feigning neurologic disease. Normally, the pupillary dilation caused by intracranial compression of the third cranial nerve will constrict with 2% pilocarpine eyedrops. A mydriatic-treated eye can be identified by full motor function of the third cranial nerve and absence of miosis after the instillation of pilocarpine. A fixed and dilated pupil in an awake and alert patient cannot be secondary to brain herniation. Although other neurologic problems may be present, in a normal-appearing patient with a fixed and dilated pupil, a pharmacologic cause is highly likely. It should be noted that legitimate patients may not recall the name of an eye medicine that they used but will usually recall whether the bottle had a red cap, as is found on all cycloplegic solutions. An unexpected mydriasis in a trusted patient may be the result of such an agent. Medications that constrict the pupil, such as pilocarpine, have a green cap. Pressure-lowering drops for glaucoma may be yellow or blue topped (β-blockers), purple topped (adrenergic agents), or orange topped (topical carbonic anhydrase inhibitors).

A fixed and dilated pupil from a pharmacologic cause may be encountered after both nasotracheal and orotracheal intubation (Fig. 62-5). In such ill or injured patients, cerebral herniation must be considered. When phenylephrine is used to constrict the nasal mucosa before nasal intubation (endotracheal tube, nasogastric tube), inadvertent spread to the eye can result in a fixed and dilated pupil. The same scenario may occur during resuscitation when endotracheal epinephrine has been instilled into the lungs and cardiopulmonary resuscitation has expelled epinephrine into the eye. In such scenarios, the affected pupil will not constrict after intraocular pilocarpine administration. Finally, a fixed and dilated pupil might occur as a result of inadvertent contamination of the eye with scopolamine after the application of a scopolamine patch.

Procedure

Instillation of mydriatic agents is similar to the administration of other eye solutions. For medicolegal purposes, note the patient’s visual acuity before instillation of the medicine. This documents that any decreased vision is not the result of the mydriatic agent. Whenever dilation is performed, note on the patient’s chart the dose and time that agents have been given to avoid confusion during subsequent neurologic evaluation.

Place the patient in a supine or a comfortable semirecumbent position. Instruct the patient to gaze at an object in the upper visual field, such as a fixture on the ceiling. Gently depress the lower lid with a finger on the epidermis. Instill a single drop of the solution into the lower lid fornix, and ask the patient to blink to spread the medication. Do not use more than a single drop because it produces reflex tearing and reduces the concentration in contact with the conjunctiva. Forewarn the patient that the medication is uncomfortable when it goes into the eyes. After the medication has been instilled, the patient may blot the eye when it is closed but should not rub it with a tissue. If the desired effect is not noted in 15 to 20 minutes, repeat the dose, but this is seldom required.

Complications

Any dilator can precipitate an attack of angle-closure glaucoma in susceptible patients.¹⁰ In the case of angle-closure glaucoma, it may take several hours before symptoms become evident. The patient often complains of smoky vision with “halos” around lights, as well as an aching pain that is sometimes severe. Nausea and vomiting may occur. If the affected eye becomes injected in association with a hazy cornea, elevated pressure on tonometry, and an oval, fixed pupil, consult an ophthalmologist immediately. Place the patient supine and administer analgesics and antiemetics. Treatment usually includes the agents suggested in Box 62-1, and later, definitive laser or surgical procedures.

Be aware that if contaminated, an eye medication can introduce infection. Most solutions contain bactericidal ingredients, but contamination of the tips of droppers can still occur (Fig. 62-6A).¹¹ Use only newly opened bottles of eye medication or single-use vials, particularly if the patient has a deep corneal injury or has recently undergone eye surgery. Promptly discard out-of-date drops and those in which crust or other material is found around the nozzle.

Forewarn the patient that any cycloplegic (in contrast to a sympathomimetic) will blur a patient’s near vision. Vision will be less blurred in adults older than 45 years, who generally have a reduced ability to focus for near vision. Although most adults will be able to drive safely, even with both eyes affected, it is advisable to have someone else drive whenever feasible. Light sensitivity caused by pupillary dilation may also be bothersome; sunglasses are sufficient for this problem.

Systemic reactions may rarely be induced by sympathomimetic and cycloplegic eyedrops.4–10 In one report of 33 cases of adverse reactions associated with 10% phenylephrine, there were 15 myocardial infarctions (11 deaths), 7 cases of precipitation of angle-closure glaucoma, and a variety of systemic cardiovascular or neurologic reactions.⁹

After instillation of eyedrops into the conjunctival sac, systemic absorption can occur through the conjunctival capillaries, as well as by way of the nasal mucosa, the oral pharynx, and the gastrointestinal tract after passage through the lacrimal drainage system. Mucosal hyperemia enhances absorption. Symptoms can often be avoided by maintaining digital pressure on the nasal canthus to occlude the puncta for several minutes after administration (Fig. 62-6B).⁴

Indications and Contraindications

Fluorescein staining is indicated for the evaluation of suspected abrasions, foreign bodies (FBs), and infections of the eye,¹⁵ including “simple” cases of conjunctivitis, which may actually be herpetic keratitis. Exposure of the face to pepper spray has been associated with corneal abrasions, and such patients should undergo fluorescein staining and be evaluated with a slit lamp or Wood’s lamp.¹⁶ Corneal defects may be seen after even a few seconds of unprotected viewing of a welder’s arc flame.

Fluorescein permanently stains soft contact lenses. Therefore, when fluorescein is used, remove soft contact lenses before instilling the fluorescein and caution the patient to not put the lenses back into the eye for several hours. Topically administered fluorescein is considered nontoxic, although reactions to a fluorescein-containing solution (not impregnated strips) have been described.¹⁷ These reports, which consist of vagal reactions¹⁸ and generalized convulsions,¹⁹ are rare, not rigorously supported, and believed to be caused by agents other than fluorescein in the solution. If using one of these fluorescein-containing solutions rather than the fluorescein-impregnated strips, be aware of these potential, yet scientifically suspect idiosyncratic reactions.

Also be aware that fluorescein dye may enter the anterior chamber of the eye in patients with deep corneal defects. This form of intraocular fluorescein accumulation is nontoxic. When the anterior chamber is viewed under the blue filter of the slit lamp, a fluorescein “flare” is visible and should not be confused with the flare reaction noted with iritis.

Procedure

Theoretically, one should not use topical anesthetics before fluorescein staining because a superficial punctate keratitis may develop in some patients from the anesthetic,¹² which can confuse the diagnosis. However, in patients who are tearing profusely and squeezing their eyes shut from an abrasion or an FB, the examination is often impossible if a topical anesthetic is not first used. Theoretical downsides notwithstanding, it is common practice to apply a local anesthetic before instilling fluorescein.

Grasp the fluorescein strip by the nonorange end and wet the orange end with 1 drop of saline. Several convenient forms are available, including a small bottle of artificial tears or a 5-mL “bullet” or “fish” of normal saline commonly used for nebulizer treatments. Alternatively, wet the strip with tap water or the recently used local anesthetic drops. Once the strip is moistened, place it gently on the inside of the patient’s lower lid (Fig. 62-7, step 1). Withdraw the strip and ask the patient to blink, which spreads the fluorescein over the surface of the eye. The key to a good examination is to have a thin layer of fluorescein over the corneal and conjunctival surfaces. If the strip is too heavily moistened before placing it in the lower fornix, the eye may become flooded with the solution, which makes evaluation difficult. If too much dye accumulates, the patient can remove the excess dye by blotting the closed eye with a tissue. Conversely, placing a dry strip in an unanesthetized eye may be irritating. Next, use a Wood lamp (4× magnification), the blue filter of a slit lamp, or simply a penlight with a blue filter to examine the eye in a darkened room (see Fig. 62-7, step 2). Check for areas of bright green fluorescence on the corneal and conjunctival surfaces. The naked eye may not be able to see small defects. Ideally, use a slit lamp with 10× or 25× magnification to examine the stained cornea before ruling out a pathologic process. A new handheld magnification device, the Eidolon Bluminator ophthalmic illuminator, produces an intense blue light from a light-emitting diode with 7× magnification (see Fig. 62-7, step 3). After completion of the fluorescein examination, irrigate excess dye from the eye to minimize damage to the patient’s clothing from dye-stained tears.

The Seidel test uses fluorescein to detect perforation of the eye.²⁰ To perform this test, instill a large amount of fluorescein onto the eye by profusely wetting the strip. Examine the eye for a small stream of fluid leaking from the globe (see Fig. 62-7, plate 4). This stream will fluoresce blue or green, in contrast to the orange appearance of the rest of the globe flooded with fluorescein.¹²

Interpretation

Fluorescein is used mainly for evaluation of corneal injuries. Although conjunctival abrasions pick up the stain, most of the staining on the conjunctiva represents patches of mucus rather than a real pathologic condition. Corneal staining is more specific for injury, and the pattern of injury often reflects the original insult.

Corneal staining patterns are illustrated in Figures 62-7 and 62-8. Abrasions usually occur in the central part of the cornea because of the limited protection of closure of the patient’s eyelids. The margins of the abrasions are usually sharp and linear if seen in the first 24 hours (see Fig. 62-7, plate 6). Circular defects are seen about embedded FBs and may persist for up to 48 hours after removal of a superficial foreign object. Deeply embedded objects may be associated with defects persisting for longer than 48 hours. Objects under the upper lid (including some chalazia) often produce vertical linear lesions on the upper surface of the cornea (see Fig. 62-7, plate 7). When vertical lesions are noted, search diligently for a retained FB under the upper lid. Overuse of hard contact lenses diminishes the nutrient supply to the cornea. The central part of the cornea sustains the most injury and thus fluoresces brightly when stained. Excessive exposure to ultraviolet light as a result of sunlamp abuse, snow blindness, or welding flashes produces a superficial punctate keratitis, which in its mildest form may not be visible without a slit lamp (see Fig. 62-7, plate 8). The central part of the cornea is the least protected by the lids, and a central, horizontal band–like keratitis can result. Herpetic lesions may develop anywhere on the cornea. Classically, these lesions are dendritic, although ulcers may also be punctate or stellate (see Fig. 62-7, plate 9).^21,22

Any area of corneal staining with an infiltrate or opacification beneath or around the lesion should alert the practitioner to the possibility of a viral,21,22 bacterial,²³ or fungal²⁴ keratitis. Obtain urgent ophthalmologic consultation so that cultures of the possible etiologic agents can be procured and appropriate treatment initiated.

Many Pseudomonas organisms fluoresce when exposed to ultraviolet light²⁵; therefore, the presence of fluorescence before the instillation of fluorescein in a red eye should suggest the possibility of infection with this organism.

Summary

Fluorescein staining is a quick and easy diagnostic procedure that should be part of every eye evaluation. The extra minute that the examination takes provides a wealth of diagnostic information on patients with eye trauma or infection. No complications are associated with the procedure with the exception of the reactions noted with the fluorescein solution, possible discoloration of soft contact lenses, and the potential for infection when premixed solutions rather than fluorescein-impregnated paper strips are used.

Indications and Contraindications

Irrigation is indicated for all acute chemical injuries involving the eyes. Irrigation may also be therapeutic in patients with an FB sensation but no visible FB. Small, unseen foreign material in the conjunctival tissues may be flushed out with irrigation. There is no contraindication to eye irrigation, but in patients with a possible perforating injury, perform the irrigation especially gently and carefully.

Equipment

The following equipment is necessary for eye irrigation:

Procedure

Complications

The only significant complication from irrigation is abrasion of the cornea or the conjunctiva. This can be a mechanical injury from trying to keep the lids open in an uncooperative patient, a small corneal epithelial defect from a Morgan irrigating lens, or fine punctate keratitis from the irrigation itself.³⁶ For this reason, do not direct the stream directly onto the cornea. If a superficial corneal defect occurs, treat it in the usual manner. Deep or penetrating corneal injuries are likely to be a result of the caustic chemical and require emergency ophthalmologic consultation. Continue to provide slow continuous irrigation pending arrival of the ophthalmologist. Some experimental evidence suggests that massive parenteral or oral ascorbic acid supplementation may prevent the development of deep corneal injury,³⁷ but such treatment has not gained universal acceptance.

Summary

Eye irrigation is easy, and complications associated with the technique are usually minimal. At times the clinician may be unsure whether a chemical injury is toxic enough to warrant irrigation. If any doubt exists, err on the side of irrigating the eye rather than omitting this vital procedure and risking progression of the eye injury.

Indications and Contraindications

Extraocular FBs must always be removed. The timing of removal and the technique required vary according to the patient’s clinical status and the type of injury. For the most part the emergency clinician can proceed directly to removal of the object via the techniques described in this section. When the patient is extremely uncooperative (e.g., an intoxicated patient, a mentally deficient patient, or a young child) or when the injury is complicated (e.g., deeply embedded object, multiple foreign objects from a blast injury, or possible globe penetration), consult ophthalmology immediately. A patient with a suspected FB or abrasion after exposure to a projectile (e.g., grinding wheel, hammering, metal objects colliding) should be rigorously evaluated for the presence of a deep intraocular FB. See further discussion later in this chapter. A penetrating injury of the cornea is of particular concern because the iris tissue may prolapse and have an appearance similar to a corneal FB (Fig. 62-13). Hence, in addition to the history of projectile exposure, an irregular pupil, especially a pear-shaped pupil, should alert the clinician that a penetrating injury might have occurred.

Globe Protection

In the evaluation of a patient in whom a penetrating injury to the globe is suspected, perform a careful expeditious examination of the eye, preferably with a slit lamp. Avoid any pressure on the eye or rapid eye movements. If perforation is obvious (e.g., teardrop pupil, flaccid globe, flat anterior chamber, prolapsed iris) or confirmed by slit lamp (positive Seidel test; see Fig. 62-7, plate 4), do not perform any procedures (except perhaps irrigation) and consult ophthalmology early for definitive diagnosis and care. Until the ophthalmologist arrives, protect the eye from further harm by keeping the patient quiet, elevating the head of the bed, and placing a protective shield over the eye. Commercial shields are available for this purpose. When a metal shield is not available, construct a makeshift protective shield with the material available (e.g., paper, plastic, or Styrofoam cups; Fig. 62-14). The protective shield helps avoid pressure on the globe and overlying tissue and assists in preventing extrusion of vitreous and other ocular contents. Extend the edges of the shield up to or beyond the bony orbital rim for this purpose. Apply adhesive tape over the shield from the forehead to the cheek to secure the shield in position.

If a patient has a globe perforation, treat with systemic antibiotics (a combination of cefazolin and gentamicin is a good initial choice), tetanus toxoid, and antiemetics in doses aggressive enough to halt vomiting.

Equipment

The following equipment is necessary for removal of an extraocular FB:

Consideration of an Intraocular FB

When examining a patient with an ocular “FB” sensation, always remain cognizant of the potential for an intraorbital or intraocular FB. Penetrating injuries represent a greater threat to visual loss than an extraocular FB does and can be disastrous if overlooked. Note that an intraocular FB can be deceptively subtle on initial evaluation. Bedside ED ultrasound is a useful adjunct for identification of intraocular FBs (Fig. 62-15).

The clinical findings are most helpful in determining which patients are at risk for a penetrating injury to the globe. An individual who complains of an FB sensation in the absence of trauma or one whose history is simply that something “fell” or “blew” into the eye is at low risk for perforation of the globe. Conversely, there is a greater probability of globe penetration in an individual who has sustained a high-velocity wound to the eye (e.g., drilling, hammering, grinding metal, blasting rock). The presence of any of the following findings on physical examination should alert the clinician to a probable intraocular FB: irregular pupil, shallow anterior chamber on slit lamp examination, prolapsed iris, positive Seidel test (see “The Fluorescein Examination,” earlier in this chapter), focal conjunctival swelling, hemorrhage, hyphema, lens opacification, and reduced intraocular pressure (IOP). Do not perform tonometry if penetrating injury to the globe is suspected. Be aware that a penetrating injury may not be associated with eye pain. If there is strong historical evidence and physical findings to support a diagnosis of globe penetration, obtain emergency ophthalmologic consultation.

An intraocular FB is often not visible on direct ophthalmoscopy. Although orbital radiography for radiopaque objects and ultrasonography of the globe have been used for indirect FB localization,15,38 computed tomography of the orbit is now considered the most useful technique (Fig. 62-16).^39,40 When plain orbital radiography is performed to look for an intraocular FB, be aware that an eyelid FB may mimic an intraocular FB.⁴¹ Patients with a suspected metallic FB should not undergo magnetic resonance imaging if the FB may be intraocular. Therapy for intraocular and intraorbital FBs must be individualized. Frequently, an ophthalmologist can localize an intraocular FB (if the vitreous is clear) with indirect ophthalmoscopy. The role of the emergency clinician is to suspect the diagnosis, protect the eye from further harm, and obtain ophthalmologic consultation. The remainder of this section addresses the problem of extraocular FBs.

Procedure

Rust Rings

A common problem with metallic FBs is that rust rings can develop (see Fig. 62-18, plate 2). They can develop within hours because of oxidation of the iron in the FB. There are two preferred techniques for removal of a rust ring. The most direct technique is to remove the ring at the same time as the FB, either with repeated picking away with a spud device or with a rotating bur. The second approach is to let the iron of the rust ring oxidize and kill the surrounding epithelial cells during a 24- to 48-hour period. After that, the rust ring will be soft and often comes out in one solid plug.⁴³ Generally, a small rust ring produces little visual difficulty unless it is directly in the line of sight. If large, a rust ring may delay corneal healing. Close follow-up is important to ensure healing of the cornea and total removal of the rust ring and FB.

Multiple FBs

If multiple FBs are present in the eye, such as from an explosion, refer the patient to an ophthalmologist. One technique that may be chosen by the ophthalmologist is to denude the entire epithelium with alcohol and remove the superficial FBs. The deeper ones gradually work their way to the surface, sometimes years later.

Aftercare

After removing the FB, an antibiotic ointment is frequently instilled. Though commonly used, the value of the ointment for superficial corneal defects after removal of an FB is unproved, and no specific standard of care is supported by scientific evidence. Conjunctival and corneal abrasions do not need patching. Data suggest that eye patching offers no benefit in healing corneal abrasions secondary to FBs.⁴⁴ If a superficial injury is sustained from the FB, instruct the patient to return only if the eye does not feel completely normal or if there is any blurred vision. The majority of superficial injuries heal without difficulty. The patient should be warned that the FB sensation might return temporarily when the anesthetic agent wears off. One animal study involving direct ocular exposure to Clostridium tetani organisms suggested that nonpenetrating ocular injuries are unlikely to lead to tetanus.⁴⁵ Tetanus prophylaxis after corneal FB removal is not standard, but it should be considered. However, tetanus prophylaxis appears to be essential for injuries that penetrate through the cornea or sclera.

Use of Ophthalmic Anesthetic Agents

Application of topical anesthetic agents can be both diagnostic and therapeutic. Relief of discomfort with a topical anesthetic often suggests, but does not ensure a conjunctival or corneal injury. An ocular irritant may also be masked by the use of these agents. Classic teaching is that patients should not self-administer anesthetic preparations. It is thought that they delay wound healing by disrupting surface microvilli and causing a decrease in the tear film layer and tear break-up time.⁴⁶ Although self-administered topical anesthetic agents are now routinely used after photorefractive keratectomy for the first 3 or 4 postoperative days, this has not become a part of ED practice.⁴⁷ The absence of protective reflexes while the patient is under the effect of the medication may encourage use of the eye and result in further corneal injury from the FB or corneal infection. Though not advised for outpatient use, topical anesthetic drops can be used safely for a few days without documented adverse effects.

Bartfield and coworkers⁴⁸ found that pain with the instillation of 0.5% proparacaine was significantly less than that with 0.5% tetracaine. As evident from Table 62-2, the anesthetic solutions commonly used have a duration of action of less than 20 minutes. Patients with a large corneal lesion may need a more extended period of pain relief. The discomfort associated with a large healing corneal lesion is usually made tolerable by bed rest, opioid analgesics, and appropriate sedatives. Even in the absence of infection or a retained FB, long-term repeated use of ophthalmic anesthetic ointments might be detrimental to corneal healing.⁴⁹

A final word of caution should be added regarding the use of ophthalmic solutions. Guaiac solutions are commonly supplied in dropper bottles similar in size and appearance to those containing ophthalmic solutions. Well-intentioned ED personnel may store the guaiac reagent bottles with the ophthalmic bottles. One should encourage both color coding of the bottles and examination of them and their labels before each use to avoid corneal injury from inadvertently instilling guaiac reagent into the eye.

Use of Ophthalmic NSAIDs

Ophthalmic nonsteroidal antiinflammatory drugs (NSAIDs) have been evaluated for their effectiveness in the treatment of traumatic corneal abrasions. Examples include ketorolac tromethamine, diclofenac, and flurbiprofen. These agents are safe to use and effective for the relief of pain associated with corneal abrasions.50–53 Topical ophthalmic NSAIDs have also been shown to be safe and effective when used for the treatment of corneal abrasions in conjunction with bandage contact lenses.⁵⁴

Complications

Complications associated with ocular FB removal are rare. The most frequent problem is incomplete removal of the FB. In such cases the epithelium has difficulty healing over the affected area, and thus the eye stays inflamed. Eventually, the diseased epithelium either sloughs off and heals or heals over the FB remnants, which are gradually absorbed. In either case, adverse effects on the eye are minimal; a minute scar on the cornea, even directly in the center, will rarely affect vision. Nonetheless, incomplete removal of a corneal foreign object warrants ophthalmologic follow-up.

Conjunctivitis may develop after removal of an extraocular FB. In most cases the bacteria producing the infection are introduced by the patient rubbing the irritated eye.

Although perforation of the globe by the clinician’s spud device is theoretically possible, this complication is exceedingly rare. Treatment of this type of corneal puncture wound consists of antibiotics, placement of an eye shield, and ophthalmologic consultation. In the absence of resultant endophthalmitis, permanent sequelae are unlikely to develop.

Epithelial injury can occur when cotton-tipped applicators are used to vigorously remove corneal FBs. Indeed, the use of cotton-tipped applicators for embedded corneal FB removal is condemned.

Summary

Ocular FBs are one of the most common eye emergencies. Searching for and removing the FB are usually straightforward. The only real trap is missing an intraocular FB. This must be ruled out if there is a history of a high-speed projectile hitting the eye or if the findings on physical examination suggest globe penetration.

Mechanism of Corneal Injury from Contact Lens Wear

Indications for Removal

Remove a contact lens in the following situations:

Contraindication to Removal

The only major problem with contact lens removal occurs when the cornea may be perforated. In this case the suction cup technique of removal, described later, is preferred.

Procedure

Lens Storage

After a contact lens is removed, store it in sterile normal saline solution. Use the patient’s own storage container and lens solution if available. A variety of alternative sterile containers are available for use in the ED. Be certain to keep the right and left lenses separate and in appropriately labeled containers. The containers should be kept with the patient until a friend or family member can procure them, or they should be locked up with the patient’s valuables.

Evaluation of a “Lost” Contact Lens

A patient may request examination for a “lost” contact lens. The patient may be unsure whether the lens is hidden under a lid, remains on the cornea, or is truly outside the eye. Evaluation of a patient with a “lost” contact should begin, as should all eye examinations, with measurement of visual acuity. Measure visual acuity preferably with a 20-ft eye chart. Diminished visual acuity in the eye with the lost contact is convincing evidence that the lens is missing. Though transparent, soft contact lenses in proper position are usually seen when viewed closely with loupes or a slit lamp. The lens forms a fine line at the point where it ends on the sclera several millimeters peripheral to the limbus. Hard contact lenses are even more evident as they change in position on the cornea.

If the contact lens is not evident on initial inspection, evert the lids as discussed in the section “Ocular FB Removal” (double eversion of the upper lid). If the lens is still not visible, place a drop of topical anesthetic in the eye. Gently sweep the upper fornix with a moistened cotton-tipped applicator while the patient looks toward the chin. If the lens is still not evident even though the patient remains insistent that it is in the eye, perform a fluorescein examination after explaining that the dye will color the lens (permanently). Evert the upper lid again and examine with an ultraviolet light source.

If the lens remains elusive, reassure the patient that a thorough examination was performed and that no object was located under the eyelids or on the cornea. Next, examine the cornea for defects that warrant antibiotic ointment and placement of a pressure patch over the eye (as discussed in “Eye Patching”). Follow-up with the patient’s eye specialist for a replacement lens and to provide further reassurance is advised. Ask the patient to retrace his movements at the time that the contact began to give trouble or was missed. Check the clothing being worn at that time and look for the lens there. A final possibility is that the patient may have accidentally placed the two lenses together in the same side of the carrying case, thereby causing them to stick together. Hence, take a methodical approach, as outlined earlier, to ensure that no lens remains hidden in the eye.

Complications of Lens Removal

A corneal abrasion can occur during lens removal. It is difficult at times to determine whether the injury was produced by the patient or was a result of removal by the clinician. Fortunately, the corneal injury is generally of a superficial nature and responds well to symptomatic care.

Summary

Contact lens removal is usually simple. Challenging situations include identifying patients at risk for corneal injury from overuse, helping patients who have lost a contact lens in the eye, and providing aftercare instructions for patients with contact lens–related problems.

Indications and Contraindications

Bandage contact lenses may be used appropriately as an adjunct for the treatment of acute corneal abrasions resulting from minor trauma when symptomatic relief or rapid return of functionality is desired. Obtain a clear history of an acute traumatic abrasion and a fluorescein stain pattern consistent with this diagnosis.

Bandage contact lenses are contraindicated when the cause of the corneal epithelial defect is suspected to be due to infection. Ensure that a corneal ulcer is not present. The hallmark fluorescein stain pattern consistent with a corneal ulcer is a round stain with blurred margins, commonly in the central visual axis (midpupil region) (see Fig. 62-19C). Pain is disproportionate to the findings. An intense ciliary flush and anterior chamber reaction (cells and flare) may also be present. Avoid the use of bandage contact lenses in patients with a history of soft contact lens use and a nontraumatic abrasion in the central part of the cornea. Follow-up for removal of the bandage contact lenses and reevaluation of the eye are required to confirm improvement and identify complications. Unreliable patients who are not likely to be compliant with follow-up are at increased risk for infection and thus not good candidates for this modality.

Equipment

Hydrophilic bandage contact lenses are available and include, but are not limited to, Biomedics 55, Ocular Sciences, Inc., San Francisco, −0.50 dioptric power, 8.6 posterior curvature, and 14.2 diameter of the lens, and Acuvue Oasys BC, zero power (plano) or −0.50 diopter, 8.4 posterior curvature, and 14.0 diameter. Acuvue Oasys has been approved by the Food and Drug Administration for up to 1 week of continuous wear.

Procedure

Assess and document the pain. Instill 1 drop of a fluoroquinolone ophthalmic solution in the affected eye as prophylaxis against infection at the time of lens placement. Use of topical anesthetics is not required, but they have often been used in the evaluation of abrasions. Use a gloved hand that has been rinsed with water to remove the talc. Orient the contact lens on the tip of the examiner’s index finger. Ensure that the lens is not inverted. The normal configuration of the lens resembles a cup, whereas an inverted lens resembles a saucer with its edges flaring outward. Another method to determine orientation of the lens is to try to close the edges or have them meet together with your fingers. If the edges curve away from each other, the lens is inverted. Direct the patient’s gaze upward and then pull the lower lid slightly downward while inserting the lens over the cornea. Ask the patient to gently blink and assess for placement. After a few minutes, reassess and again document whether pain is present. Instruct the patient to return for follow-up in 1 day. On return, remove the soft lens as described earlier, assess vision, document pain, and reevaluate the eye.

Complications

Because of the hypoxic microenvironment of the cornea, covering the cornea with a bandage contact lens could increase the opportunity for an infection to occur. Patients who do not disclose the use of soft contact lenses are at increased risk for corneal ulcers. Some patients may experience “tight lens syndrome” because of a lens that does not fit well or from drying out as the lens is exposed to the elements. Bandage contact lenses are usually of a generic size and thus do not offer a precise fit, but they are in place only for a short duration. Signs and symptoms may include redness, eye irritation, burning, a dry sensation, blurry vision, halos around objects, and lack of mobility of the contact lens over the cornea. Lack of mobility can reduce oxygen tension and thereby cause corneal edema and an even tighter lens. Rewetting solutions can improve hydration. Removal of a tight fitting lens was described earlier.

Summary

Bandage contact lenses have been shown to be safe, effective, and comfortable in the treatment of corneal abrasions. Careful patient selection and proper technique will optimize this treatment modality when appropriately indicated for routine ED use. Patients will experience significantly decreased pain without the use of narcotic analgesics, significantly increased functionality, and decreased time away from work.

Tonometric Techniques

Three tonometric techniques are reliable and clinically useful for estimating IOP:

The Schiøtz tonometer actually measures total IOP (initial pressure plus the pressure added by the weight of the tonometer and the plunger). Friedenwald⁸⁹ empirically found that a “rigidity coefficient” could be introduced to allow an estimation of the true IOP. One must be aware, however, that calculated conversion tables for Schiøtz tonometers use an average estimate of the rigidity coefficient and hence are not accurate when eye rigidity is altered (e.g., after scleral buckle procedures for retinal detachment or with extreme myopia).

Measurement of IOP in the ED by tonometry is a technique available to most emergency clinicians. Tonometry is not a standard procedure for many eye-related complaints, but in the following special situations tonometry it may be particularly helpful:

Tonometry may also be considered in the following scenarios:

Contraindications to Tonometry

Tonometry is relatively contraindicated in eyes that are infected unless one is using a device such as the Tono-Pen XL, which uses a sterilized cover.² Sterilize a tonometer before and after applying it to a potentially infected eye. Measure infected eyes with either a noncontact tonometer or a device with a covered tip (e.g., Tono-Pen). Swab the contact portions of any device with alcohol and allow it to dry before use on another eye. Not all viruses are destroyed by cleansing with alcohol. Hydrogen peroxide is effective in deactivating the human immunodeficiency virus responsible for acquired immunodeficiency syndrome (AIDS). Ultraviolet sterilization, cold sterilizer bathing of the footplate and plunger, and ethylene oxide sterilization have all been advocated as alternatives to sterilizing the tip of the Schiøtz tonometer. The Schiøtz tonometer may also be used with sterile disposable coverings (marketed as Tonofilm). Nonetheless, defer measurement of IOP in an obviously infected eye until a subsequent visit to the ED or private clinician unless the red eye demands an immediate determination of IOP.

Examples of indications for immediate tonometry in the setting of a red eye are suspected angle-closure glaucoma (acute onset of redness and pain in the eye with smoky vision, a cloudy cornea, and a fixed pupil in mid-dilation, often with headache and nausea) and iritis (ciliary injection with photophobia), in which secondary angle-closure glaucoma or corticosteroid-induced changes in pressure may occur. Reported cases of conjunctivitis spread by tonometry predominantly tend to be viral infections. Particular effort should be made to avoid use of the instrument on patients with active facial or ocular herpetic lesions or those who may have AIDS.

The presence of corneal defects also represents a relative contraindication to tonometry.3,13 Use of a tonometer on an abraded cornea may lead to further injury and is commonly deferred until a subsequent visit. Patients who cannot maintain a relaxed position (e.g., because of significant apprehension, blepharospasm, uncontrolled coughing, nystagmus, or uncontrolled hiccups) are unlikely to permit an adequate examination and can sustain a corneal injury when sudden movements occur during an examination. Furthermore, tonometric examination, with the exception of the palpation technique (through the lids) and the noncontact method, should not be performed on a cornea without complete anesthesia.

Tonometry should not be performed on a patient with a suspected penetrating ocular injury.² Globe perforation may be exacerbated by pressure on the globe with resultant extrusion of intraocular contents. Slit lamp examination can be used for detection of a possible perforation.

Procedure

Complications

When tonometric instruments are used properly and reasonable precautions are taken, complications are unusual. An eye with preexisting corneal injury should be spared the additional trauma of tonometer placement. Corneal abrasions can be produced by ocular movement during testing. In particular, patients with uncontrollable nystagmus, hiccups, or coughing or those who are extremely apprehensive should not be subjected to tonometry. Infection can be transmitted by use of the instrument. Careful cleansing of the device and avoidance of tonometry in patients with obvious conjunctivitis, corneal ulcers, or active herpetic lesions should minimize the risk of spreading the infection to the unaffected eye or to subsequent patients. Although protective coverings can be placed over the tonometer contact, tonometry can usually be postponed in the aforementioned individuals until the risk for infection is minimal. Extrusion of ocular contents with penetrating injuries is a potential, but rare complication.

Indications and Contraindications

The slit lamp can be used in the majority of eye examinations. It is especially useful in the ED for the diagnosis of corneal abrasions, FBs, and iritis.³¹ The slit lamp facilitates FB removal and is also used in conjunction with most applanation tonometers. Portable slit lamp instruments are readily available (Fig. 62-24) but seldom used in the ED; thus emergency practitioners generally have access only to a stationary, upright device. Therefore, in the absence of a portable device, a slit lamp examination is contraindicated in patients who cannot tolerate an upright sitting position (e.g., those with orthostatic syncope).

Equipment

The slit lamp has three essential components: a binocular microscope mounted horizontally, a light source that can create a beam of variable width, and a mechanical assembly to immobilize the patient’s head and manipulate the microscope and light source. The location and arrangement of the knobs that control these components vary in devices made by different manufacturers. Usually, by simply turning each knob and watching the results, one can quickly master a new machine. Figure 62-25 illustrates the location of the functional controls on one particular instrument.

First, locate the on/off switch for the instrument. Frequently, this switch incorporates or is adjacent to a rheostat that provides two or three different power settings. The lowest setting is adequate for routine examination and will preserve bulb life. One can use a high-intensity setting when examining the anterior chamber with a narrow slit beam. Often, these controls are located on a transformer placed beneath the table to which the slit lamp has been attached. The second knob that one should find is the locking nut for the mechanical assembly. Loosen the nut so that the assembly can be moved.

Make adjustments so that the patient is comfortable while sitting with the head in the device. Ask the patient to press the forehead firmly against the head rest with the chin in the chin rest. By varying the height of the table and height of the chin rest, one should be able to maximize comfort of the patient’s neck and back. Adjust the chin rest to align the patient’s eye level with the mark on the head rest support rods.

The binocular microscope has a control for varying the magnification. Usually, low powers such as 10× or 16× are the most useful. Use a higher power to examine the anterior chamber for cells and flare and when the cornea is examined in minute detail. Adjust the binocular interpupillary distance to match that of the examiner. Focus the eyepieces by moving the instrument forward and backward until the narrowed vertical beam is sharpest on the patient’s cornea when viewed with the unaided eye. Then, while viewing through each eyepiece individually, adjust the focus of each to produce a sharp image of the anterior surface of the cornea.

Notice that the light source is mounted on a swinging arm. Find the knobs that adjust the width and the height of the light beam. Click various filters in as needed, usually white and blue filters for standard examination. Alter the angle of the slit lamp beam from vertical to horizontal. The vertical alignment is preferred for routine examinations in the ED.

Both the microscope and the light source are mounted on swivel arms linked at their base to a movable table. Change the position of this table by pushing on any part of it. Use the joystick on the table for finer movements. Vary the height of the microscope and the light source by twisting either the joystick or a separate knob at the base, depending on the design of the instrument.

Procedure

There are three setups that every slit lamp operator must know.⁹⁷ The first is for an overall screening of the anterior segment of the eye. For examination of the patient’s right eye, swing the light source to your left at a 45-degree angle while the microscope is directly in front of the patient’s eye. Set the slit beam to the maximum height and the minimum width using the white light. To scan across the patient’s cornea, first focus the beam on the cornea by moving the entire base of the slit lamp forward and backward. Then move the whole base left and right to scan across the cornea. The 45-degree angle between the microscope and the light source is the default position. The most common mistake is to try to scan by swinging the arm of the light source in an arc; this does not work because the light beam will remain centered on the same point of the patient’s eye. Scan across at the level of the conjunctiva and the cornea and then push slightly forward on the base or joystick and scan at the level of the iris. The depth of the anterior chamber is easily appreciated with this low-magnification setup (Fig. 62-26). When the depth of the anterior chamber is reduced, suspect a corneal perforation or a predisposition to angle-closure glaucoma.

Use this basic setup to examine the conjunctiva for traumatic lesions, inflammation, and FBs. Examine the eyelids for hordeolum, blepharitis, or trichiasis. Completely evert the lids (as described earlier in the section “Ocular FB Removal”) in conjunction with the slit lamp examination to permit evaluation of the undersurface of the upper lid for FB retention.

Corneal FB removal can be enhanced by use of the slit lamp. In particular, the instrument allows stabilization of the patient’s head. Magnification also minimizes corneal injury during FB or rust ring removal. The upper eyelid may be immobilized with a cotton-tipped applicator, as discussed previously. The clinician’s hand can be steadied against the patient’s nose, cheek, or forehead or against the support rods of the head rest. The patient should be instructed to stare straight ahead at a fixed light or at the clinician’s ear during removal of the FB.

The second setup is essentially the same as the first but uses the blue filter. The purpose is to identify any areas of fluorescein staining. After fluorescein is applied, “click” the blue filter into position and widen the beam to 3 or 4 mm. A patient can tolerate a wider beam without photophobia if it is blue. Search for corneal defects (as discussed earlier in “The Fluorescein Examination”) with this setup. The blue filter may also be used with applanation tonometry, as discussed earlier in “Tonometry.”

The purpose of the third setup is to search for cells in the anterior chamber—either the white cells of iritis or the red cells of a microscopic hyphema. Shorten the height of the beam to 3 or 4 mm and make it as narrow as possible. Switch the microscope to high power. Focus the beam on the center of the cornea and then push forward slightly so that it is focused on the anterior surface of the lens. Pull the joystick back again to a focus point midway between the cornea and the lens, where it will be focused on the anterior chamber (Fig. 62-27). Keep the beam centered over the pupil so that there is a black background. Normally, the aqueous humor of the anterior chamber is totally clear. Small particles seen floating up or down through the beam are usually circulating cells. If the beam lights up the aqueous like a searchlight in the fog, the examiner has found the protein flare that accompanies iritis. Note that fluorescein can penetrate an abraded cornea and produce a fluorescein flare on slit lamp evaluation. To avoid confusion, some clinicians prefer to examine for anterior chamber flare before the stain is used. A variety of conditions evaluated by the slit lamp are pictured in Figure 62-28.

Central Renal Artery Occlusion

A patient with central retinal artery occlusion (CRAO) has generally experienced a recent sudden painless (complete or nearly complete) unilateral loss of vision. On examination there is an afferent pupillary defect (i.e., sluggish or nonreactive pupil in the affected eye with direct illumination and a normal consensual response) and reduced visual acuity. Immediately after the event the fundus may appear nearly normal; however, it soon becomes pale and a classic “cherry-red spot” in the macula may be evident as a result of patent choroidal vessels showing through the transparent fovea (Fig. 62-29).

Orbital Compartment Syndrome

Acute facial trauma or recent retrobulbar anesthesia may produce retrobulbar hemorrhage with sufficient pressure to compromise the ophthalmic artery and result in an orbital compartment syndrome (Fig. 62-32). A form of posttraumatic glaucoma may also occur when the retrobulbar hematoma forces the globe against the eyelids. In this case, IOP rises precipitously because the globe is in a relatively closed space as a result of the firm attachment of the eyelids to the orbital rim by the medial and lateral canthal ligaments. The optic nerve and its vascular supply and the central retinal artery are compressed, which can result in ischemia and subsequent visual loss. In this situation, emergency lateral canthotomy may be considered for relief of the pressure on the eye. It would not be considered a standard of care for most emergency clinicians to possess the skills for this procedure, but in the proper scenario, it may be a prudent intervention.

In this situation, ophthalmoscopic evaluation reveals a blanched ophthalmic artery in the presence of obvious retrobulbar pressure and ecchymosis around the eye. The patient exhibits decreased visual acuity, and an afferent pupil defect is often seen. IOP is markedly elevated but may be relieved by emergency lateral canthotomy and cantholysis. Such a procedure needs to be performed quickly because the ischemic retina will not retain function if it is deprived of blood for a long period.

Indications and Contraindications

Early globe reduction is indicated to relieve symptoms and minimize visual impairment. Attempts at reduction in the ED are relatively contraindicated when there is obvious rupture of the globe.

Technique

Before globe reduction, perform a rapid eye examination to document visual acuity, range of eye motion, pupillary reactivity, and any evidence of globe rupture (see earlier discussion).¹⁰⁶ Place the patient in a recumbent position and administer a topical ocular anesthetic agent (e.g., 0.5% proparacaine). When the lashes are visible, ask an assistant to apply steady outward and upward traction while the globe is gently pushed behind the lids. Use gloved fingers to apply steady scleral pressure and to manipulate the globe back into the orbit. When the lashes cannot be grasped, introduce a lid retractor behind the lid to provide countertraction. Others recommend placing a suture through the anesthetized skin of each lid to provide countertraction.

After the procedure, repeat the eye examination to document visual acuity and extraocular movement. It is not uncommon for return of full visual function to be delayed for several days or occasionally longer.

Complications

It is common with this procedure for lashes to be retained in the conjunctival fornices. Evaluate for and remove any free lashes to prevent corneal injury. Edema, retrobulbar hemorrhage, or orbital deformity may prevent outpatient reduction. When reduction is not possible in the ED, saline drops should be applied to the globe and a noncontact eye shield used.

Aftercare

Patients with spontaneous luxation and no visual impairment in whom the globe is easily reduced warrant follow-up within 24 to 48 hours. Instructions to avoid potential triggering maneuvers should be given. Recurrent luxation may warrant lateral tarsorrhaphy. Further evaluation of potential precipitating factors can be pursued on an outpatient basis.

Patients with traumatic luxation are at greater risk for underlying ophthalmic injury and warrant emergency consultation. A computed tomography scan of the orbit is helpful for evaluating both the soft tissue and the bony structures about the globe.

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