Ocular Foreign Body Removal
Winnie T. Whitaker
Wendy J. Pomerantz
Introduction
Foreign bodies commonly become lodged on the eye surface, whether blown in by wind or propelled at high velocity. Patients with ocular foreign bodies often present to the emergency department (ED) because of pain or, in the case of young children, irritability. Foreign bodies may be located superficially in the cornea or conjunctiva or may be embedded. It is important to distinguish a superficial foreign body from a penetrating eye injury. Objects embedded in the cornea are not always associated with pain and therefore may be difficult to identify.
A high index of suspicion for an ocular foreign body necessitates careful examination of the eye. The promptness of the exam and the technique used depends on the type of injury and the patient’s ability to cooperate. Management of ocular foreign bodies may be challenging in children. While irrigation does not require full cooperation, a child must be completely still if an instrument is to be used for foreign body removal. For children in whom irrigation is not successful, sedation or general anesthesia is occasionally required.
Anatomy and Physiology
The conjunctiva covers the sclera and lines the inner surfaces of the upper and lower eyelids (see Fig. 45.1). It secretes a mucous film that helps to capture particulate matter on the eye surface. The cornea is a tough covering over the iris a few millimeters thick and consists of three layers: the outer surface, the stroma, and the endothelium. The outer surface is composed of five layers of epithelial cells, which, unlike the skin epithelium, is not keratinized. Below this, the stroma gives the cornea structural integrity. It is this layer that glows yellow-green when a corneal abrasion is stained with fluorescein. A single-cell layer of endothelium below the stroma regulates fluid and nutrient supply.
The eye will respond to the presence of a foreign body with injection of the conjunctiva, tearing, and blinking. The patient usually has associated pain; however, not all foreign body injuries, even with globe perforation, are associated with pain. Visual acuity may be affected if the foreign body is in the visual axis or if associated corneal edema is present (1).
Intraocular foreign bodies of inert materials, such as some plastics or glass, may be well tolerated and may not necessitate immediate removal. Metallic foreign bodies precipitate inflammatory reactions that can further damage the eye, whereas organic materials increase the risk of infection (2).
Indications
All foreign bodies in the eye must be removed; however, not all are removed immediately. In some circumstances, such as with the uncooperative child or when equipment is needed that is not available, removal may best be performed in an ophthalmologist’s office or in an operating room. A corneal foreign body is best removed as soon as possible, because the cornea may epithelialize over the foreign body in several hours (1) and make removal more difficult.
Foreign bodies may be located on the inner surface of the eyelids, in the fornices, on bulbar conjunctiva and sclera, or on the cornea or may have penetrated the globe. Corneal foreign bodies are most commonly found on the lower two thirds of the cornea.
Examination to rule out foreign body is indicated when a child complains of foreign body sensation. Foreign body sensations are not uncommon, however, and may represent other conditions, such as conjunctivitis. A patient may complain of foreign body sensation when the foreign body is no longer in the eye but has resulted in a residual corneal abrasion.
Vertical, linear corneal abrasions often result when foreign bodies adherent to the inside of the upper lid injure the cornea during blinking. If noted on eye examination with fluorescein, a thorough search for an ocular foreign body on the upper lid is indicated.
The presence of a metallic foreign body in the eye, even for a few hours, may result in a brownish rust ring at the site of the injury. Removal of the foreign body and the rust ring is required, but the rust ring can be removed at follow-up by an ophthalmologist (see “Complications.”).
A ruptured globe should be considered in patients with a history of high-velocity wounds and in those with hyphema, irregular or sluggish pupil, and a decrease in visual acuity. Attempts at foreign body removal by the emergency physician are contraindicated if a ruptured globe is suspected, if lack of patient cooperation precludes safe removal, or if the foreign body appears to be embedded. In these circumstances, and when attempts at foreign body removal are unsuccessful or the foreign body is incompletely removed, immediate referral to an ophthalmologist is indicated. When the possibility of a ruptured globe exists, the eye should be protected with an eye shield. This keeps the patient from rubbing the eye and prevents any contact of the eye that can cause extrusion of orbital contents.
Indications for immediate ophthalmologic consultation include the presence of an embedded foreign body, the presence of multiple foreign bodies, unsuccessful foreign body removal attempts, a patient who is unable to cooperate with the procedure, any indication of possible ruptured globe such as hyphema or an irregular or sluggish pupil, and a decrease in visual acuity.
Equipment
Visual acuity chart
Topical anesthetic drops (e.g., proparacaine HCl 0.5% or tetracaine HCl 0.5%)
Sterile water, syringe, and plastic catheter
Sterile cotton-tipped applicators
Fluorescein drops or strips
Wood’s lamp or slit lamp
Eye spud or 25-gauge needle on 3-mL syringe
Topical dilating drops (e.g., homatropine 2% or 5%, cyclopentolate 0.5% or 1%, tropicamide 1%)
Antibiotic ointment or drops
Procedure
Evaluation for Ocular Foreign Body
Emergency personnel should ask the child or parent how the foreign body entered the eye. An object blowing or falling into the eye is unlikely to penetrate the globe, whereas an object entering the eye at high velocity, such as when hammering on metal or working with industrial tools, should alert the clinician to the possible rupture of the globe.
Before the eye is anesthetized, the physician may ask the older child where the foreign body sensation is located. Kaye-Wilson demonstrated that adult patients indicating a foreign body sensation in either the temporal, nasal, or central regions were generally correct in identifying the area of the cornea where a foreign body was located. Localization to the lower lid indicated a foreign body in the lower half of thecornea. Localization of the foreign body sensation to the upper lid was less reliable, and foreign bodies were located in any region of the cornea (3). This information may be particularly useful to the physician who does not have access to a slitlamp.
It is often difficult for children to cooperate with techniques involving direct removal of ocular foreign bodies. Minimal cooperation may be required for the irrigation technique. Pharmacologic sedation can be helpful in children who may not be able to remain still during foreign body removal (Chapter 33). Administering pharmacologic sedation requires a physician trained in its use and careful monitoring of the patient. If the patient is sedated and the attempt at foreign body removal is unsuccessful, immediate ophthalmologic referral is indicated.
A thorough examination of the eye is necessary for all children in whom a foreign body of the eye is suspected (Chapter 45). Any associated injuries, especially a ruptured globe, must be identified before attempts to remove an ocular foreign body are made. Intraocular foreign bodies (within the globe rather than superficial) may be subtle in up to 20% of patients (4) and should be suspected if the patient has a history of high-velocity injuries. Diffuse, chemotic subconjunctival hemorrhage raises the suspicion of corneal laceration and therefore a ruptured globe (4,5).
Careful observation of pupil size, shape, and reactivity is critical. Prolapse of the iris with distortion of pupillary shape indicating a ruptured globe may look deceptively like a foreign body. If a ruptured globe is clinically suspected, a metal shield is placed over the eye with no pressure applied to the eye; an eye patch is contraindicated. No drops or ointments are instilled in the eye. The patient is instructed to have nothing by mouth. Broad-spectrum intravenous antibiotics are administered, and tetanus immunization, if not current, is given. Urgent ophthalmologic consultation is obtained. Plain radiographs and computerized tomography may be helpful in ruling out an intraocular foreign body, but magnetic resonance imaging should be avoided if any possibility of intraocular metal foreign body exists (6).
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