eMedicine Specialties > Ophthalmology > Cornea
Corneal Foreign Body
Updated: Jun 30, 2008
Introduction
Background
Corneal foreign body is foreign material on or in the cornea, usually metal, glass, or organic material.
Pathophysiology
Corneal foreign bodies generally fall under the category of minor ocular trauma. Small particles may become lodged in the corneal epithelium or stroma, particularly when projected toward the eye with considerable force.
The foreign object may set off an inflammatory cascade, resulting in dilation of the surrounding vessels and subsequent edema of the lids, conjunctiva, and cornea. White blood cells also may be liberated, resulting in an anterior chamber reaction and/or corneal infiltration. If not removed, a foreign body can cause infection and/or tissue necrosis.
Frequency
United States
Foreign bodies are one of the most frequent causes of visits for ophthalmic emergencies. Sometimes, the foreign body may not be present at the time of examination, having left the residual corneal abrasion with resultant pain.
Superficial corneal foreign bodies are much more common than deeply embedded corneal foreign bodies. The possibility of an intraocular foreign body must always be considered when a patient presents with a history of trauma.
In major league baseball, 33% of all eye injuries are corneal abrasions; in the National Basketball Association, corneal abrasions account for 12% of all eye traumas.
International
No difference in frequency is observed internationally.
Mortality/Morbidity
Generally, superficial foreign bodies that are removed soon after the injury leave no permanent sequelae. However, corneal scarring or infection may occur. The longer the time interval between the injury and treatment, the greater the likelihood of complications.
If the foreign body fully penetrates into the anterior or posterior chambers, then it is officially an intraocular foreign body. In this case, eye morbidity is much more common. Damage to the iris, lens, and retina can occur and severely damage vision. Any intraocular foreign body can lead to infection and endophthalmitis, a serious condition possibly leading to loss of the eye.
Sex
Similar to other traumatic injuries, the incidence in males is much higher than in females.
Age
Similar to most other traumatic injuries, the peak incidence is found in the second decade and generally occurs in people younger than 40 years.
Clinical
History
The activities of the patient and their surroundings are important. The time and the place of the injury, along with exactly how it occurred, are important. For example, a patient who was working with a high-speed grinding machine is likely to have an intraocular foreign body that may be occult in nature, whereas a patient who was working underneath a car when rust fell gently on the eye is likely to have only an external injury.
- Patients may complain of the following:
- Pain (typically relieved significantly with topical anesthesia)
- Foreign body sensation (typically relieved significantly with topical anesthesia)
- Photophobia
- Tearing
- Red eye
Physical
- Patients may present with the following:
- Normal or decreased visual acuity
- Conjunctival injection
- Ciliary injection, especially if an anterior chamber reaction occurs
- Visible foreign body
- Rust ring, especially if a metallic foreign body has been embedded for hours to days
- Epithelial defect that stains with fluorescein
- Corneal edema
- Anterior chamber cell/flare
- The patients may be asymptomatic if the foreign body is below the epithelial or conjunctival surface. Over a period of a few days, epithelium often grows over small corneal foreign bodies, with a resultant reduction in pain.
- If a corneal infiltrate is present, an infectious cause needs to be considered. Foreign bodies can cause a small sterile inflammatory reaction around the foreign object. However, if a large infiltrate, any corneal ulceration, a significant anterior chamber reaction, or significant pain is present, it should be managed as an infection. See Keratitis, Bacterial.
Causes
Corneal foreign body injury can occur just about anywhere. They commonly occur both at home and at work.
- Generally, the cause is accidental trauma. The type of trauma helps to determine the likelihood of a superficial versus a deep or even intraocular foreign body.
- Materials include small pieces of wood, metal, plastic, or sand.
- The injury usually occurs in windy weather or when working with power tools. Dirt, sand, or small portions of leaves frequently are blown into the eye and adhere to the superficial cornea.
Differential Diagnoses
Corneal Abrasion
Foreign Body, Intraocular
Keratitis, Bacterial
Keratitis, Fungal
Other Problems to Be Considered
Any eye after trauma, especially with a foreign body, needs to be evaluated for a ruptured globe and an intraocular foreign body.
Consider the possibility of an underlying corneal sensation problem. In this setting, corneal abrasions may heal poorly and may recur easily if a problem exists with corneal sensation. See Keratopathy, Neurotrophic.
Workup
Laboratory Studies
- 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 Studies
- To exclude intraocular or intraorbital foreign body, consider B-scan ultrasound, orbital CT scan (1-mm axial and coronal cuts), and/or ultrasound biomicroscopy (UBM). If the foreign body is metallic, the initial study may include orbital x-ray films. If plain films are negative and a high suspicion still exists for intraocular foreign body, the previously mentioned studies are indicated. These studies should be complemented by a full-dilated examination by an ophthalmologist.
- Avoid MRI if a possible history of metallic foreign body exists.
- UBM, with high-frequency ultrasound, is often useful to rule out a foreign body embedded in the anterior sclera. These foreign bodies may not be visible because of their nature (eg, glass) or overlying opacity (eg, conjunctival hemorrhage).
Other Tests
- A Seidel test is performed to rule out corneal perforation in the setting of a deep corneal foreign body.
- The lower and upper lids need to be everted to look for additional foreign bodies. If a superficial foreign body is suspected but not found, double eversion of the upper lid to search for a foreign body is required.
Procedures
- Corneal foreign bodies are removed using a sterile foreign body spud or needle after topical anesthesia. Antibiotic is applied to the eye before and after the removal. Cotton-tipped applicators often are not appropriate because of the large surface area of cotton that touches the cornea, potentially creating a large epithelial defect. Because of the risk of corneal scarring and inadvertent globe perforation, this procedure should be completed using a slit lamp biomicroscope and performed by a clinician who is well trained and experienced in corneal foreign body removal.
- Rust rings that remain in the cornea after removal of a metallic foreign body may require removal with a rust ring drill. This procedure also should be performed using a slit lamp biomicroscope by a clinician who is well trained and experienced in rust ring removal because of the risk of corneal scarring and inadvertent globe perforation.
Treatment
Medical Care
Management objectives include relieving pain, avoiding infection, and preventing permanent loss of function.
- Topical antibiotic drops (eg, polymyxin B sulfate-trimethoprim [Polytrim], ofloxacin [Ocuflox], tobramycin [Tobrex] qid) or ointment (eg, bacitracin [AK-Tracin], ciprofloxacin [Ciloxan] qid) should be prescribed until the epithelial defect heals to prevent infection.
- Topical cycloplegic (cyclopentolate 1% qd/bid) can be considered for pain and photophobia, although a review of the literature shows that they are not effective1,2
- Pressure patch or bandage contact lens is best avoided (unless the epithelial defect is >10 mm2 and then bandage contact lens may be the better option).1,3,4 The following scenarios represent high risk for the patient to develop permanent vision loss. Do not patch if any of the following are present:
- A chance of a perforation of the globe exists.
- A corneal infiltrate is present.
- A chance of a retained intraocular foreign body is possible.
Surgical Care
- Remove the foreign body using irrigation, a sterile needle, or a foreign body removal instrument. Do not remove if likelihood of penetration through more than 25% of the cornea exists.
- Remove a rust ring with an Alger brush or automated burr. Only those clinicians who are trained in and regularly perform this procedure should complete it.
Consultations
- Immediately refer to an ophthalmologist in case of the following:
- Hyphema (blood in the anterior chamber)
- Diffuse corneal damage (focal or diffuse opacity)
- Scleral or corneal laceration
- Lid edema
- Diffuse subconjunctival hemorrhage
- Posttraumatic dilation of pupil or abnormal shape of pupil
- Abnormally shallow or deep anterior chamber compared to the fellow eye
- Persistent corneal defect or corneal opacity
- Any case with possible full penetration of the cornea or sclera
Medication
An uncomplicated case in which the foreign body is removed can be treated with standard antibiotics. If a large epithelial defect is present, an antibiotic ointment is placed prior to the use of a patch. Complicated cases should be seen by an ophthalmologist immediately and prior to any therapy. For example, if an infiltrate is present, the ophthalmologist may want to scrape and plate the lesion before any antibiotic is instilled in the eye.
Antibiotics
Prevent infection of an open corneal abrasion.
Polymyxin B sulfate-trimethoprim (Polytrim)
For ocular infections, involving cornea or conjunctiva, resulting from strains of microorganisms susceptible to this antibiotic. Available as a solution and ointment. Trimethoprim and polymyxin B are rarely sensitizing, and they have a wide spectrum of action in combination.
Gram-positive: S aureus, S epidermidis, Streptococcus species (group A beta-hemolytic and nonhemolytic), S pneumoniae
Gram-negative: P aeruginosa, H influenzae, H aegyptius, E coli, K pneumoniae, P mirabilis (indole-positive), Proteus species (indole-negative), E aerogenes, C freundii, C diversus, A calcoaceticus, M lacunata (some strains), S marcescens
Dosing
Adult
1 gtt qid
Pediatric
<2 months: Not established
>2 months: 1 gtt qid
Interactions
None reported
Contraindications
Documented hypersensitivity; viral, fungal, and mycobacterial infections of the eye
Precautions
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Do not use in deep ocular infections or in those likely to become systemic; prolonged use of antibiotics or repeated therapy may result in bacterial or fungal overgrowth of nonsusceptible organism; if redness, irritation, swelling, or pain persists or increases, discontinue use immediately and reevaluate therapy; patient should avoid contamination of the dropper
Tobramycin (Tobrex)
Like other aminoglycosides, the bactericidal activity of tobramycin is accomplished by specific inhibition of normal protein synthesis in susceptible bacteria, but very little presently is known about this action. May inhibit bacterial mRNA synthesis, causing inhibition of bacterial growth.
Dosing
Adult
1 gtt qid
Pediatric
Administer as in adults
Interactions
Effects of this drug are decreased when used concurrently with gentamicin
Contraindications
Documented hypersensitivity
Precautions
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Do not use in deep-seated ocular infections or in those that may become systemic; prolonged use of antibiotics may result in bacterial or fungal overgrowth of nonsusceptible organisms
Ofloxacin (Floxin)
Pyridine carboxylic acid derivative with broad-spectrum bactericidal effect.
Dosing
Adult
1 gtt qid
Pediatric
Administer as in adults
Interactions
None reported
Contraindications
Documented hypersensitivity
Precautions
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Do not use in ocular infections that may become systemic; superinfections may occur with prolonged or repeated antibiotic therapy
Ciprofloxacin (Ciloxan)
Inhibits bacterial growth by inhibiting DNA gyrase.
Dosing
Adult
0.5-inch ribbon in subconjunctival sac qid
Pediatric
Administer as in adults
Interactions
None reported
Contraindications
Documented hypersensitivity; viral, mycobacterial, and fungal eye infections; avoid coadministration with steroid combinations after uncomplicated removal of a foreign body from cornea
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
A white crystalline precipitate located in superficial portion of corneal defect may occur (onset starts in 1-7 d); precipitate usually is cleared within 2 wk and does not adversely affect clinical course or outcome; do not use in ocular infections that may become systemic; superinfections may occur with prolonged or repeated antibiotic therapy
Bacitracin ointment (AK-Tracin, Baciguent)
Prevents transfer of mucopeptides into growing cell wall, inhibiting bacterial growth.
Dosing
Adult
0.5-inch ribbon in subconjunctival sac qid
Pediatric
Administer as in adults
Interactions
None reported
Contraindications
Documented hypersensitivity; vaccinia, varicella, epithelial herpes simplex keratitis, mycobacterial infections, and fungal diseases of the eye; patients using steroid combinations after uncomplicated removal of a corneal foreign body
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Ophthalmic ointments may delay healing of corneal epithelia; in deep-seated infections of the eye, supplement with systemic medications; prolonged use may result in overgrowth of nonsusceptible organisms
Gatifloxacin (Zymar)
Fourth-generation fluoroquinolone ophthalmic indicated for bacterial conjunctivitis. Elicits a dual mechanism of action by possessing an 8-methoxy group, thereby inhibiting the enzymes DNA gyrase and topoisomerase IV. DNA gyrase is involved in bacterial DNA replication, transcription, and repair. Topoisomerase IV is essential in chromosomal DNA partitioning during bacterial cell division. Indicated for bacterial conjunctivitis due to Corynebacterium propinquum, S aureus, Staphylococcus epidermidis, Streptococcus mitis, S pneumoniae, or H influenzae.
Dosing
Adult
Days 1-2: Instill 1 gtt into affected eye(s) q2h while awake; not to exceed 8 administrations/d
Days 3-7: Instill 1 gtt into affected eye(s) up to 4 times/d while awake
Pediatric
<1 year: Not established
>1 year: Administer as in adults
Interactions
None reported
Contraindications
Documented hypersensitivity
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
For ophthalmic use only; commonly causes conjunctival irritation, increased lacrimation, corneal inflammation, or papillary conjunctivitis; less common adverse effects include conjunctival hemorrhage, dry eye, eye discharge, eye irritation, eye pain, eyelid swelling, headache, red eye, reduced visual acuity, or taste disturbance
Cycloplegics
For comfort of the eye and to prevent iris adhesion in cases of traumatic iritis.
Cyclopentolate HCl 0.5%-1.0% (Cyclogyl)
Cyclopentolate is an anticholinergic agent that induces relaxation of the sphincter of the iris and ciliary muscles. When applied topically to the eyes, it causes rapid, intense cycloplegic and mydriatic effects that reach a peak in 15-60 min; recovery usually occurs within 24 h. The cycloplegic and mydriatic effects are slower in onset and longer in duration in patients who have dark pigmented irises.
Dosing
Adult
1 gtt qd/tid
Pediatric
Administer as in adults
Interactions
Decreases effects of carbachol and cholinesterase inhibitors
Contraindications
Documented hypersensitivity; narrow-angle glaucoma
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Exercise caution in patients (eg, elderly patients) where increased intraocular pressure may be present; can cause toxic anticholinergic systemic adverse effects (common in children, especially infants) but incidence rare when used sparingly; compressing lacrimal sac by digital pressure for 1-3 min, following application, may minimize systemic absorption
Follow-up
Further Inpatient Care
- Foreign bodies that present any potential for intraocular penetration must by explored in the operating room. These injuries should be explored within 24 hours of initial examination.
Further Outpatient Care
- Follow up every 2 days until the epithelial defect is well healed and any corneal infiltrates have resolved.
- Perform a gonioscopy after the resolution of the problem, and consider annual follow-up care for intraocular pressure 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.
Deterrence/Prevention
- Wear safety goggles in any situation (eg, sports, construction, workshops, industry) that has a high risk of particles or objects flying into the eyes.
Complications
- Rust ring usually is due to an iron foreign body and can be removed carefully at a slit lamp using a burr.
- Infectious keratitis is common in organic injuries and in neglected cases. It may need to be scraped for smears and cultures. It needs to be treated aggressively with topical antibiotics.
- Globe perforation occurs in metal-on-metal and similar high-speed type injuries. It also can occur if a corneal ulcer is neglected. It requires surgical repair.
Prognosis
- Good prognosis exists unless a rust ring or scarring involves the visual axis. If infection develops, prognosis is more guarded. Globe penetrating injuries and intraocular foreign bodies are separate categories and have much worse prognoses.
Patient Education
- Remind patients of the importance of wearing protective eyewear in any high-risk situation.
- Eyes should not be rubbed while working with wood or metal pieces.
- If a foreign body enters the eye, the eye should not be rubbed and no attempt should be made by the patient to remove the foreign body.
- For excellent patient education resources, visit eMedicine's Eye and Vision Center. Also, see eMedicine's patient education articles Eye Injuries and Foreign Body, Eye.
Miscellaneous
Medicolegal Pitfalls
- Vision should be checked in each eye separately prior to proceeding with any extensive ocular examination or treatment.
- When a corneal foreign body encroaches on the visual axis, before proceeding, inform the patient about the potential loss of visual acuity because of unavoidable scarring. This conversation should be well documented to avoid negative clinicolegal ramifications.
- If the clinician is unable to rule out the possibility of a perforating ocular injury, apply a shield to the eye and immediately refer the patient to a nearby hospital or ophthalmology practice.
- Remember that an intraocular foreign body may show no external eye findings and that a full-dilated examination is necessary to visualize all aspects of the eye.
- 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.
References
Peate WF. Work-related eye injuries and illnesses. Am Fam Physician. Apr 1 2007;75(7):1017-22. [Medline].
Carley F, Carley S. Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Mydriatics in corneal abrasion. Emerg Med J. Jul 2001;18(4):273. [Medline].
Arbour JD, Brunette I, Boisjoly HM, Shi ZH, Dumas J, Guertin MC. Should we patch corneal erosions?. Arch Ophthalmol. Mar 1997;115(3):313-7. [Medline].
[Best Evidence] Turner A, Rabiu M. Patching for corneal abrasion. Cochrane Database Syst Rev. 2006;(2):CD004764. [Medline].
Augeri PA. Corneal foreign body removal and treatment. Optom Clin. 1991;1(4):59-70. [Medline].
Aziz MA, Rahman MA. Corneal foreign body--an occupational hazard. Mymensingh Med J. Jul 2004;13(2):174-6. [Medline].
Howell RM. Corneal abrasion. eMedicine Journal [serial online]. 2007;Available at http://www.emedicine.com/emerg/topic828.htm.
Hulbert MF. Efficacy of eyepad in corneal healing after corneal foreign body removal. Lancet. Mar 16 1991;337(8742):643. [Medline].
Jayamanne DG, Bell RW. Non-penetrating corneal foreign body injuries: factors affecting delay in rehabilitation of patients. J Accid Emerg Med. Sep 1994;11(3):195-7. [Medline].
Kaiser PK. A comparison of pressure patching versus no patching for corneal abrasions due to trauma or foreign body removal. Corneal Abrasion Patching Study Group. Ophthalmology. Dec 1995;102(12):1936-42. [Medline].
Kay-Wilson LG. Localisation of corneal foreign bodies. Br J Ophthalmol. Dec 1992;76(12):741-2. [Medline].
Newell SW. Management of corneal foreign bodies. Am Fam Physician. Feb 1985;31(2):149-56. [Medline].
Yang X. Removal of corneal foreign bodies that project into the anterior chamber: use of a suture needle. Am J Ophthalmol. Jun 2000;129(6):801-2. [Medline].
Keywords
foreign material, cornea, foreign object, corneal abrasion, globe perforation, ocular trauma, ocular injury, rust ring
Contributor Information and Disclosures
Author
Mounir Bashour, MD, CM, FRCS(C), PhD, FACS, Assistant Professor of Ophthalmology, McGill University; Clinical Assistant Professor of Ophthalmology, Sherbrooke University; Medical Director, Cornea Laser and Lasik MD
Mounir Bashour, MD, CM, FRCS(C), PhD, FACS is a member of the following medical societies: American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus, American College of International Physicians, American College of Surgeons, American Medical Association, American Society of Cataract and Refractive Surgery, American Society of Mechanical Engineers, American Society of Ophthalmic Plastic and Reconstructive Surgery, Biomedical Engineering Society, Canadian Medical Association, Canadian Ophthalmological Society, Contact Lens Association of Ophthalmologists, International College of Surgeons US Section, Ontario Medical Association, Quebec Medical Association, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.
Medical Editor
Kilbourn Gordon III, MD, FACEP, Urgent Care Physician
Kilbourn Gordon III, MD, FACEP is a member of the following medical societies: American Academy of Ophthalmology and Wilderness Medical Society
Disclosure: Nothing to disclose.
Pharmacy Editor
Simon K Law, MD, PharmD, Assistant Professor of Ophthalmology, Jules Stein Eye Institute; Chief of Section of Ophthalmology Surgical Services, Department of Veterans Affairs Healthcare Center, West Los Angeles
Simon K Law, MD, PharmD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.
Managing Editor
Christopher J Rapuano, MD, Professor, Department of Ophthalmology, Jefferson Medical College of Thomas Jefferson University; Co-Chairman of the Cornea Service, Co-Chairman of Refractive Surgery Department, Wills Eye Institute
Christopher J Rapuano, MD is a member of the following medical societies: American Academy of Ophthalmology, American Society of Cataract and Refractive Surgery, Eye Bank Association of America, Pennsylvania Medical Society, and Philadelphia County Medical Society
Disclosure: Allergan Honoraria Speaking and teaching; Allergan Consulting fee Consulting; Alcon Honoraria Speaking and teaching; Inspire Honoraria Speaking and teaching; RPS Ownership interest Other
CME Editor
Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri
Disclosure: Nothing to disclose.
Chief Editor
Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology
Disclosure: Nothing to disclose.
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