Patients typically report getting something in the eye or complain of FB sensation. FBs that overlie the cornea may affect vision. Tearing, conjunctival injection, headache, and photophobia may also be present. The most important consideration is the possibility of a penetrating globe injury. One must elicit a meticulous history about the mechanism of injury, such as hammering metal on metal or using power lawn equipment.
Management and Disposition
Topical anesthetic drops (eg, 0.5% proparacaine or tetracaine) facilitate examination and removal. If superficial, removal with saline flush may be attempted before using a sterile eye spud or small (25-gauge) needle. Consider topical antibiotic drops or ointment for the residual corneal abrasion. Tetanus prophylaxis is indicated. A “short-acting” cycloplegic (cyclopentolate 1% or homatropine 5%) may benefit patients with headache or photophobia. FB or “rust ring” removal should be conducted using slit-lamp microscopy and only by a physician skilled in rust ring removal due to the risk of corneal perforation or scarring.
Corneal Foreign Body. Metallic corneal foreign body with a rust ring and surrounding inflammation at 8 o’clock. Note corneal haziness extending out from the foreign body. (Photo contributor: Aubrey Mowery, MSN, MPH, CPNP.)
Always evert the upper lid and search carefully for a FB. A FB adherent to the upper lid abrades the cornea, producing the “ice-rink” sign, caused by multiple linear abrasions.
Vigorous attempts to remove the entire rust ring are not warranted. This may await emergency department or ophthalmology follow-up in 24 hours.
The tip of an 18-gauge needle can be bent 90 degrees using sterile forceps or the needle cap to make a “scoop” for FB and rust ring removal.
Corneal Foreign Body. Metallic corneal foreign body with a rust ring and surrounding inflammation at 8 o’clock embedded for 2 days. (Photo contributor: Lawrence B. Stack, MD.)