and Corneal Foreign Bodies

Christopher J. Rapuano


BASICS


DESCRIPTION


• Foreign material on or in the cornea or conjunctiva


– Most commonly metallic or organic material


EPIDEMIOLOGY


Incidence


• One of the most common causes of emergent ophthalmic visits:


– Peak incidence in second decade


– More common in males


RISK FACTORS


• Use of power tools/machinery:


– Windy weather


GENERAL PREVENTION


Use of safety glasses


PATHOPHYSIOLOGY


Small foreign material becomes imbedded in conjunctiva, corneal epithelium, or stroma.


ETIOLOGY


Often work related


DIAGNOSIS


HISTORY


• The patient may have pain, foreign body (FB) sensation (both relieved with topical anesthetic), photophobia, tearing, and redness


• May or may not have a known history of trauma


• Important to know mechanism of injury including the material and velocity of the FB



ALERT


Be highly suspicious for intraocular foreign body (IOFB) or scleral laceration with high-velocity injuries (e.g., metal on metal).


PHYSICAL EXAM


• Signs can include normal or decreased visual acuity (VA), eyelid edema, conjunctival injection, anterior chamber reaction, corneal edema, and/or infiltrate.


• Always check VA.


• Meticulous slit lamp biomicroscopy examination is performed to assess the location, size, and depth of the FB.


• Metallic foreign bodies can leave a residual rust ring.


• A long-standing FB can lead to infection, inflammation, and necrosis of surrounding tissue.


• Check anterior chamber for inflammation as a result of traumatic iritis.


• Always look for signs of IOFB. Gonioscopy examination is performed if appropriate to check the angle for FB.


• Clues for IOFB or occult lacerations include:


– Chemosis


– Subconjunctival or anterior chamber hemorrhage


– Poor VA


– Afferent pupillary defect


– Irregular pupil


– Iris transillumination defects


– Abnormally deep or shallow anterior chamber


– Hypotony


– Vitreous hemorrhage


– Traumatic cataract


• Fluorescein staining may highlight conjunctival or corneal defects and may indicate an FB under the upper lid.


• If no signs of a globe rupture, evert the upper lid and sweep the fornices to search for foreign bodies.


• Dilated fundus exam to look for IOFB


DIAGNOSTIC TESTS & INTERPRETATION


Lab


Corneal or conjunctival cultures should be performed if the surrounding tissue appears infected.


Imaging


An anterior segment ultrasound biomicroscopy, gentle B-scan ultrasound, or orbital CT scan (1 mm coronal and axial cuts) can be helpful to rule out IOFB. MRI should be avoided if there is a possibility the FB contains metal.


Diagnostic Procedures/Other


A positive Seidel test at the slit lamp proves that the anterior chamber has been entered.


DIFFERENTIAL DIAGNOSIS


• Conjunctival, corneal, scleral laceration


• IOFB


• Corneal abrasion


• Ruptured globe


• Dry eyes


TREATMENT


MEDICATION


First Line


Conjunctival FB (after FB removal):


• Topical antibiotic ointment or drops q.i.d. for 5–7 days is recommended.


Corneal FB (after FB removal):


• Topical antibiotic ointment or drops q.i.d. for 7 days is prescribed. The author recommends a topical fluoroquinolone


Second Line


• Cycloplegics can be added for anterior chamber inflammation.


• Oral NSAIDS can be used for pain control; topical NSAIDS can also be used for pain management but are avoided by the author due to small risk of corneal thinning.



ALERT


Under no circumstances should topical anesthetics be given or prescribed to the patient for pain control.

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Nov 9, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on and Corneal Foreign Bodies

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