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Intraocular Foreign Bodies

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Ovid: 5-Minute Sports Medicine Consult, The


Intraocular Foreign Bodies
Kevin N. Waninger
Basics
Epidemiology
  • The presentation, outcome, and prognosis of intraocular foreign bodies (IOFBs) are variable.
  • Adults: Often in industrial accidents (hammering, metal on metal contact, blast injury, high-speed machines like drills, grinding wheels, saws, windy weather)
  • Children: Often with explosives, weapons, windy weather
  • Similar to most other traumatic injuries, the peak incidence is found in the 2nd and 3rd decades and generally in males younger than 40 yrs of age.
  • Mostly accidental work-related injuries, although increasingly related to home and leisure activity accidents
Risk Factors
Protective eyewear of appropriate quality (3 mm of polycarbonate) prevents virtually all injuries from IOFBs (1).
General Prevention
  • Wear appropriate protective eyewear in any situation (sports, construction, workshops, industries) that may lead to a higher risk of particles or objects getting into the eyes.
  • The eyes should not be rubbed while working with wood or metal pieces. If a foreign body should enter an eye, no attempt should be made by the patient to remove the foreign body if perforation is suspected. If perforation is not suspected, eye irrigation may be attempted to wash out any potential foreign bodies.
  • Use particular caution with explosives.
Diagnosis
  • Superficial foreign bodies that are removed after the injury typically leave no permanent sequelae. However, corneal scarring and infection may occur, and the longer the time interval between the eye injury and subsequent treatment, the greater the likelihood that complications may occur.
  • Morbidity greatly increases if the foreign body penetrates into the anterior or posterior chambers, as damage to the iris, lens, and retina can occur and severely affect visual acuity. Any IOFB can lead to infection and endophthalmitis, which can threaten loss of the eye.
Pre Hospital
  • Place a shield over the eye, both eyes if IOFB with globe perforation is suspected.
  • Position patient sitting upright.
History
  • The activities of the patient and their surroundings at the time of injury are important and should lead to a high index of suspicion for IOFB.
  • Common complaint: “Something flew into my eye”
  • Past medical history should be obtained, including prior surgeries, medications, allergies, tetanus status, last meal (if surgery is a possibility).
  • Visual acuity and correction with contacts (daily- or extended-wear) or glasses
  • Inquire whether the patient was wearing eye protection at the time of injury. Try to find out what type of eyewear, if so, and whether they are still intact.
  • Composition of suspected foreign body is important:
    • Organic: Wood, soil, plants, insect parts
    • Inorganic material: Oxidizes (iron, copper)
    • Inert material: Paint, glass, plastic, fiberglass, nonoxidizing metals, sand
Physical Exam
  • Note that IOFBs can be deceptively subtle on initial presentation. The symptoms of an ocular foreign body may range from irritation to intense, excruciating pain. This is dependent on the location, material, and type of injury.
  • Note that high-speed projectiles may not produce pain or visual acuity problems initially, as the foreign body may be located below the epithelial or conjunctival surface. A fully dilated eye exam may be necessary to visualize all aspects of the eye.
  • Eye pain/foreign body sensation (typically relieved significantly by topical anesthesia)
  • Redness
  • Tearing
  • Blurred/decreased vision
  • Light sensitivity (photophobia)
  • Visible foreign body or rust ring
  • Difficulty opening the eye
  • A complete examination of both eyes is necessary, including visual acuity and fields, lid eversion to check for retained FB, pupil size, shape, and reactivity.
  • Slit lamp, fluorescein, and funduscopic examinations should be performed as soon as possible. Perform intraocular pressures if there is no evidence of perforation.
  • Minimize manipulation of the globe and exercise caution during examination if perforation is suspected to prevent prolapse of ocular contents.
  • Document corneal irregularities, wound location and size, if visible, as well as blood in the anterior chamber or vitreous.
  • Note normal or decreased visual acuity, any conjunctival injection, ciliary injection (especially if an anterior chamber reaction occurs), any visible foreign body, any rust ring (especially if a metallic foreign body has been embedded for at least several hours), any epithelial defect that stains with fluorescein, any corneal edema, and anterior chamber cells/flare.
  • If a corneal infiltrate is present, an infectious cause needs to be considered.
  • Use the Seidel's sign to look for globe penetration that is not so obvious. In the case of a positive Seidel's sign, the oozing aqueous humor at the site of the penetration through the cornea appears under ultraviolet light as a “dark waterfall,” clearing away excess fluorescein on the cornea.
  • Minimize manipulation of the globe and exercise caution during examination to prevent prolapse of ocular contents.
  • Document baseline visual acuity, visual fields, pupillary size, shape and reactivity, corneal irregularities, wound location and size, depth of the anterior chamber, iris and lens condition, blood in the anterior chamber or vitreous, gaze restriction, and external examination.
  • History, physical, and imaging studies should be used to assess number, size, shape, location, composition, visibility, trajectory, and accessibility of the IOFB.
Diagnostic Tests & Interpretation
Lab
  • Unless an infectious corneal infiltrate/ulcer or an intraocular foreign body is suspected, no laboratory work is indicated.
  • Infectious corneal infiltrates/ulcers generally require scrapings for smears and cultures.
Imaging
  • Orbital CT with 0.5-mm axial and coronal cuts
  • Radiographs have low sensitivity for small and nonmetallic objects, but can be used for metallic FBs if CT not available.
  • β-scan US, with caution due to risk of ocular prolapse
  • MRI: Initially contraindicated due to risk of magnetic properties, but may be used to localize small nonmetallic IOFBs after metallic IOFBs ruled out by CT scan
  • Ultrasound biomicroscopy
Differential Diagnosis
  • Corneal abrasion
  • Conjunctival and corneal foreign bodies
  • Corneal perforation
  • Ruptured globe
  • Other trauma without retained IOFB
  • Corneal ulcer
  • Keratitis, bacterial and/or fungal
Treatment
  • No topical medications or ointments if globe perforation is suspected
  • Topical anesthetic to assist examination and decrease discomfort (proparacaine/tetracaine) unless with obvious globe perforation
  • Minimize nausea and vomiting to prevent resultant increase in intraocular pressure.
  • Pediatric patients may require sedation to facilitate examination and FB removal.
  • Shield should be placed over involved eye, avoiding any pressure on the globe.
  • Both eyes should be shielded to prevent contralateral eye movement if globe perforation is suspected.
  • Topical antibiotics may be started until the epithelial defect heals to prevent infection.
  • If perforation is suspected, systemic antibiotics prior to surgical intervention may be started.
  • Topical corticosteroids may be used to decrease inflammation (controversial, must rule out herpes infection)

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  • Initiate topical cycloplegic agents for pain and photophobia.
  • Update tetanus if indicated
  • Liberal use of pain medications; these injuries may be very painful.
  • Corneal patching is no longer recommended (2)[A].
ED Treatment
  • Deep penetrating foreign bodies:
    • Deep penetrating foreign bodies require immediate referral to an ophthalmologist, because endophthalmitis and permanent scarring may occur, and delayed surgical removal is associated with significantly worse outcomes.
  • Superficial foreign bodies:
    • Superficial foreign bodies can be removed manually by those who are trained in the technique. Anesthesia (topical anesthetic ophthalmic solution) is necessary prior to foreign body removal and usually facilitates initial eye examination.
    • The procedure's benefits, risks, and complications must be explained to the patient, or to the patient's representative, and an informed consent obtained.
    • A negative Seidel's sign must be obtained.
    • If the foreign body is superficial, the eye should be irrigated to moisten the cornea. Removal of the foreign body should be attempted by using a gentle rolling motion with a wetted cotton-tipped applicator. Pressure should not be applied, as this may push the foreign body deeper into the cornea or scrape it, creating a large corneal abrasion. An attempt to wash the foreign body off the cornea should be done by directing a stream of normal saline at an oblique angle to the cornea.
    • An embedded foreign body should not be removed with irrigation or with a cotton-tipped applicator.
    • An embedded foreign body should be removed by using a gentle flicking motion with an eye spud, if available, or with a 25- or 27-gauge needle. Using a slit lamp to visualize the FB and to immobilize the patient's head, the hub of the needle may be placed on the tip of a cotton swab or a 3-mL syringe. The cornea may be approached from the side, with the needle in a plane tangent to the cornea and the bevel away from the corneal surface. This minimizes the chance of corneal perforation. Once dislodged from its embedded position on the cornea, remaining corneal debris can be removed with a wetted cotton-tipped applicator.
    • Within 3 hr, iron-containing foreign bodies oxidize, leaving a rust stain on adjacent epithelial cells, which can delay healing and act as an irritant focus. Removal with 25-gauge needle or a pothook burr at the same time as FB removal, or within 24 hr, is recommended. Rust rings that remain in the cornea after removal of a metallic foreign body that cannot be manually removed will require ophthalmology removal with a rust ring drill (1,3,4)[B].
    • Documenting a negative Seidel's sign after the removal of a corneal foreign body is good practice, especially after using a sharp instrument, to confirm that no iatrogenic penetration of the cornea occurred during the procedure (5,6)[C].
Medication
  • Topical anesthetics prolong epithelial healing and should never be prescribed for home pain relief (1,4,7)[C].
  • Ophthalmic NSAIDs appear to be useful for decreasing pain in patients with corneal injury (8)[A].
Additional Treatment
Referral
  • Patients who present to the emergency department with emergent conditions should be referred to an ophthalmologist on the day of presentation. Patients with urgent conditions can be seen the following day.
  • Emergent conditions:
    • Hyphema (blood in the anterior chamber)
    • Diffuse corneal defect or opacity
    • Laceration of the cornea or sclera
    • Single dilated pupil or an abnormally shaped pupil
    • A more deep or shallow anterior chamber (when compared to the other eye)
    • Possible penetration of the globe
    • Positive Seidel's sign
    • Multiple foreign bodies
    • Extremely uncooperative patient (eg, young child, intoxicated individual, patient with mental disability)
  • Urgent conditions:
    • Significant lid edema
    • Diffuse subconjunctival hemorrhage
    • Large corneal abrasion
    • Corneal ulceration
In-Patient Considerations
Initial Stabilization
If the examination in the office or the emergency department is not good enough to rule out a foreign body or ocular perforation, then an examination under anesthesia should be considered. This is especially true for children, where there should be a low threshold to examine the patient in the operating room.
Admission Criteria
Foreign bodies that present any potential for intraocular penetration must by explored in the operating room. These injuries should be explored within 24 hr of initial examination.
Discharge Criteria
  • All corneal foreign bodies: Follow-up in 24–48 hr for reexamination.
  • If rust rings were not completely removed, follow-up should be made with ophthalmology within 24 hr.
Ongoing Care
Follow-Up Recommendations
Patient Monitoring
  • Follow up every 1–2 days until the epithelial defect is well healed and corneal infiltrates have resolved.
  • No activity or positioning restrictions are necessary once the wound heals.
  • A gonioscopy should be performed after resolution of the problem. Annual follow-up care for intraocular pressure should be planned if the severity of trauma raises a suspicion for angle-recession glaucoma in later life.
  • A dilated fundus examination should be performed on a routine basis after any injury severe enough to potentially damage the retina.
Patient Education
Eye protection when taking part in risky activities (eg, hammering, mowing the lawn) is strongly recommended.
Prognosis
Prognosis is good unless a rust ring or scarring involves the visual axis. If infection develops, prognosis is more guarded. Globe-penetrating injuries and intraocular foreign bodies have much worse prognoses, but reading vision is usually retained/regained, if properly treated.
Complications
Endophthalmitis, corneal scarring, elevated intraocular pressure, cataract, retinal detachment, proliferative vitreoretinopathy, and metallosis (eg, chalcosis, siderosis) are possible complications.
References
1. Kuhn F, Wong DT, Giavedoni L. Foreign body, intraocular. Updated December 3, 2008. Accessed: September 19, 2009.
2. Turner A, Rabiu M. Patching for corneal abrasion. Cochrane Database Syst Rev. 2006;CD004764
3. Weichel ED, Yeh S. Techniques of intraocular foreign body removal. Tech Ophthalmology. 2009;7:45–52.
4. Bashour M. Corneal foreign body. Emedicine.medscape.com. Updated June 30, 2008. Accessed September 19, 2009.
5. Yeh S, Colyer MH, Weichel ED. Current trends in the management of intraocular foreign bodies. Curr Opin Ophthalmol. 2008;19:225–233.
6. Coa CE, Hackett TS. Foreign body removal, cornea. Emedicine.medscape.com. Updated May 21, 2009. Accessed on September 19, 2009.
7. Greven CM, Engelbrecht NE, Slusher MM, et al. Intraocular foreign bodies: management, prognostic factors, and visual outcomes. Ophthalmology. 2000;107:608–612.
8. Weaver CS, Terrell KM. Evidence-based emergency medicine. Update: do ophthalmic nonsteroidal anti-inflammatory drugs reduce the pain associated with simple corneal abrasion without delaying healing? Ann Emerg Med. 2003;41:134–140.
Additional Reading
Peate WF. Work-related eye injuries and illnesses. Am Fam Physician. 2007;75:1017–1022.
Codes
ICD9
  • 930.0 Corneal foreign body
  • 930.1 Foreign body in conjunctival sac
  • 930.2 Foreign body in lacrimal punctum


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