Corneal Abrasions and Removal of Corneal or Conjunctival Foreign Bodies

CHAPTER 66 Corneal Abrasions and Removal of Corneal or Conjunctival Foreign Bodies



Grant C. Fowler


Patients with “something in the eye,” a corneal or conjunctival abrasion or foreign body, are common for primary care clinicians. In most cases, the management is uncomplicated and can be completed in the clinician’s office; however, knowledge of certain principles should help avoid impaired vision or blindness.


A detailed history is important, especially knowing what the patient was doing when he or she first noticed a problem. For instance, was the patient wearing eye protection? Was he or she around hammered metal? Did he or she come into contact with a high-velocity foreign body?


NOTE: In the past, corneal abrasions were treated with eye patching and mydriatics; however, there is little evidence to support such therapy, and eye patching may even impede healing. Consequently, most clinicians now use ophthalmic nonsteroidal anti-inflammatory drugs (NSAIDs) and an ophthalmic antibiotic for treatment. Some of the evidence supporting this approach is discussed further in the “Technique” section. Also, if a slit lamp is available, a more thorough evaluation of the eye may be performed for a corneal abrasion or foreign body (see Chapter 67, Slit-Lamp Examination). In the absence of a slit lamp, this chapter indicates when a slit-lamp referral is required.



Fluorescein Examination of the Cornea and Conjunctiva



Indications



• Unilateral foreign body sensation, hypersensitivity to light, excess tearing, or pain—especially on opening or closing the eye

• Red eye

• Eye trauma

• After airbag deployment in automobile accidents

• Unilateral, persistent eye irritation in contact lens wearer

• History of exposure to ultraviolet (UV) light from such sources as a welding torch, sunlight, or a tanning bed (UV light can penetrate the cornea even when the patient’s eyes are closed if protective lenses are not worn)

• Mild chemical exposure to eye

• Neonates or infants with persistent crying, unilateral tearing, hypersensitivity to light, or conjunctival inflammation

• Eye discharge in mask-ventilated newborn or heavily sedated or paralyzed adults on a ventilator

NOTE: Hypersensitivity to light, excess tearing, and painful or red eye are also signs and symptoms of glaucoma (see Chapter 68, Tonometry). If there is no foreign body sensation, the patient should be evaluated for acute glaucoma.



Contraindications


Patients with the following symptoms should be referred to an ophthalmologist after they have been provided initial urgent care:


• Suspected high-velocity injury to the eye (e.g., patients exposed to metal hammering or heavy machinery). High-speed metallic or nonmetallic fragments can penetrate the globe while only causing minimal symptoms and damage to the cornea. As a result, significant internal damage must be excluded. If penetration of the globe is apparent, fluorescein staining is usually avoided because it may make further evaluation or surgery more difficult.

• A hyphema, lens opacification, scleral tear, abnormal anterior chamber examination, or irregularity of the pupil. These findings suggest that the globe has been penetrated, and an ophthalmologist needs to be involved. Orbital x-ray films may confirm a metal foreign body. A spiral computed tomography scan or ultrasonography may also confirm a metal foreign body; magnetic resonance imaging is contraindicated if there is a possible ferromagnetic object.

• Long-standing (>24 hours) inflammation as evidenced by iritis, photophobia, or ciliary blush. These findings suggest the presence of an intraocular foreign body or a more serious injury and require slit-lamp examination and evaluation by an ophthalmologist.

NOTE: A pressure patch is contraindicated in a penetration injury of the globe or a complex lid laceration. For such injuries, a nonpressure protective eye shield should be applied before referral. Metal shields are manufactured for this purpose, or a nonpressure shield can be fashioned from a paper cup (Fig. 66-1). All patches and shields should be taped in the same direction, from the medial forehead across the eye and toward the ear.


• Exposure to caustic or acidic media. Immediate management includes copious irrigation for at least 15 minutes. (It can begin at home with tap water from a shower or hose.)

• Mild chemical exposure. If the clinician is not knowledgeable about or comfortable with managing the case after contacting a Poison Control Center, the patient should be referred.

• Ruptured globe.

• Uncooperative patient. (Infants may have to be sedated; see Chapter 7, Pediatric Sedation and Analgesia.)

image

Figure 66-1 Nonpressure patch to protect ruptured globe. A metal shield or a paper cup can be used.



Equipment



• Snellen chart at 6 m (20 ft), or an equivalent visual acuity chart (Fig. 66-2). If a chart is unavailable, ask the patient to read a magazine at arm’s length. If the patient cannot do so, measure and record the distance at which the patient can count fingers.

• Topical ophthalmic anesthetic such as 0.5% proparacaine (e.g., Alcaine, Kainair, Ophthaine, Ophthetic, Paracaine, Proparacaine), unless contraindicated (e.g., ruptured globe or allergy to local anesthetics).

• Sterile fluorescein sodium strips. (Because fluorescein is incompatible with preservatives effective against Pseudomonas and Proteus, multidose dropper bottles of fluorescein solution should not be used. Inoculating abraded corneal epithelium with bacteria could cause infection, permanent scarring, or blindness.)

• Bright white light source (a single-point source such as a penlight is preferable).

• Cobalt-blue light source (Wood’s lamp is adequate).

• An 8- to 10-power magnification lens (loupes, a magnifying glass, a colposcope, or an ophthalmoscope on the +20 to +40 diopter setting).

• Sterile cotton-tipped applicators.

• Isotonic ophthalmic irrigant (e.g., Dacriose, Ringer’s lactate, normal saline).

• Facial tissues (e.g., Kleenex).

image

Figure 66-2 A, Illiterate E chart. B, Near-vision chart.



Preprocedure Patient Preparation


The indications for the examination should be explained to the patient as well as any risks or alternatives. The patient needs to know what will occur during the examination, and that he or she may be asked to direct vision to certain locations. Eyedrops and dye will probably be necessary to enhance the examination. Contact lenses should be removed before the eye is stained (fluorescein can stain them permanently). Before instilling fluorescein, the patient should be warned that objects in his or her vision may temporarily appear yellow. Tears may also remain yellow for a short time after the examination and might stain skin or clothing, at least temporarily, so the patient should avoid rubbing his or her eyes or drying tears on something that might stain.


Patients should be instructed to breathe normally and, especially children, may be asked at certain times to remain as still as possible. Children may need assistance with holding still. Patients should know to blink normally unless their eye is being held open by the examiner or they are asked to hold their eye open. They should be aware of the need for the examiner to touch their face and even to pull on their eyelids. Before instilling the topical anesthetic, tell the patient that it may cause a burning sensation until the eye becomes numb. Because patients with a corneal abrasion are usually hypersensitive to light, let them know when you are going to need a bright white light for only a short while, and that the room will otherwise be darkened. The remainder of the examination is done with a blue light, which should be more comfortable. Reassurance that this bright light will not cause permanent visual damage is usually appreciated. In fact, patients should be told that the reason for using this bright light (in most cases) is to prevent permanent damage to their vision. After the clinician has located the necessary equipment, the lights in the room can be dimmed during the remainder of the examination.


If an abrasion is diagnosed, emphasize the need for the patient to follow up daily with the clinician until it is completely healed. This will detect early complications such as infection. Instruct the patient to call the office if persistent or recurrent symptoms occur. Patients should also be instructed not to drive if the abrasion impairs their vision or depth perception.



Technique



1 Check and document visual acuity in both eyes before instilling topical anesthetic. Documentation of baseline visual acuity before the topical anesthetic is applied is important because initial discomfort due to the anesthetic (e.g., burning, stinging) may later be suspected by the patient as having caused impaired vision. If the patient normally wears corrective lenses (e.g., glasses) for refractive error, check visual acuity with refraction. After the acuity check, the patient will probably be most comfortable in the supine position for the remainder of the examination.

NOTE: If the patient’s corrective lenses are not available, a pinhole myopia corrector can be used. These are commercially available, but they are also easy to make. With an 18-gauge needle, punch 8 to 10 holes within a 5-cm (2-inch) circle on an index card. Have the patient select the hole that provides the best vision when viewing the Snellen chart. This effectively corrects the patient’s vision.


2 Hand the patient a tissue and instill one to two drops of topical anesthetic into his or her affected eye. (This is not mandatory but does facilitate patient cooperation and comfort.)

3 Inspect the affected eye, briefly but thoroughly, with a bright white light source, and compare it with the opposite eye. The sclera should be intact. The anterior chamber should be free of pus or blood. The iris should be normal in size and shape. The pupil should be normal in size, shape, and reactivity, and it should be symmetric with the other pupil unless there is a history of asymmetry (anisocoria). If all of these conditions are not met, the patient should be referred to an ophthalmologist.

4 Eversion of the upper lid is usually necessary to examine the entire conjunctiva (Fig. 66-3). After grasping the lower lid and applying traction, examine the conjunctiva beneath it as well. Inspect the entire bulbar and palpebral conjunctiva for trauma, foreign body, or other sources of symptoms, such as a hordeolum or an ingrown or inverted eyelash. Examine carefully the groove about 2 mm from the lash margin of the everted lid. Tiny objects frequently lodge here and may not be immediately visible. Use the ophthalmoscope for magnification if necessary. For a foreign body, refer to the “Corneal or Conjunctival Foreign Body Removal” section later in this chapter. Older patients often have ingrown hairs (trichiasis) that can cause a foreign body sensation (see Chapter 39, Epilation of Isolated Hairs [Including Trichiasis]). Trichiasis most frequently involves the lower lid, and if there are only a few hairs, they can be plucked out with fine forceps. The patient with many hairs should be referred for electrolysis of the roots.

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Corneal Abrasions and Removal of Corneal or Conjunctival Foreign Bodies

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