Ocular Foreign Body

Material that lodges on or in the superficial structures of the eye: conjunctiva (including subtarsal), cornea and fornices. It accounts for a large proportion of eye emergency visits.

• Common types: metal particles (grinding, drilling, welding), wood and plant matter, glass, sand and dust, insect parts, eyelashes, cosmetic particles, and contact lens fragments.
• Risk groups: manual workers without eyewear, construction workers, mechanics, gardeners, wind exposed people, motorcyclists.
• Consequences: corneal abrasion, rust ring (iron), infection (bacterial and fungal keratitis, especially with vegetable matter), scarring, and missed intraocular foreign body with high velocity injury.
• Subtarsal foreign body causes vertical linear corneal abrasions on the upper cornea from blinking.

• Foreign body sensation, tearing, blepharospasm, photophobia, redness, blurred vision, pain on blinking.
• Visible particle on the cornea or conjunctiva, localised injection around the particle, rust ring (brown halo after 6 to 24 hours with an iron fragment), corneal infiltrate or ulcer (late), anterior chamber reaction.
• Vertical linear epithelial scratches on fluorescein staining indicate a subtarsal foreign body.
• High speed projectiles may have no visible mark; features of intraocular foreign body include a small entry wound, irregular pupil, localised lens opacity, hyphaema or low pressure.

• Mechanism and duration history, and ask directly about hammering metal on metal, grinding without goggles, or explosions.
• Visual acuity, penlight and slit lamp examination with fluorescein, double eversion of the upper lid, fornix inspection, and Seidel test if full thickness penetration is suspected.
• Dilated fundus examination if there is any suspicion of intraocular foreign body; orbital CT with thin cuts for high velocity injury or unexplained signs; B-scan ultrasound only if open globe excluded.
• Tetanus status.

• Topical anaesthesia (proparacaine 0.5 percent or oxybuprocaine 0.4 percent) for removal; do not prescribe anaesthetic drops for home use.
• Conjunctival and subtarsal foreign bodies: irrigation with saline or removal with a moistened cotton bud after eversion of the lid.
• Corneal foreign body: remove under the slit lamp using a 25 or 27 gauge needle on a syringe held tangentially to the surface or a sterile cotton bud, spud or burr; remove the rust ring completely using a battery driven burr (the residual ring can be left 1 to 2 days to loosen if deeply embedded); avoid damaging the deep stroma.
• After removal: antibiotic ointment (chloramphenicol 1 percent ointment or ofloxacin 0.3 percent drops four times daily for 5 to 7 days), cycloplegic (cyclopentolate 1 percent once if severe pain or iritis), oral analgesia (paracetamol 1 g four times daily, ibuprofen 400 mg three times daily), and topical NSAID drops (ketorolac 0.5 percent four times daily for 2 days) if desired; patching is not necessary.
• Vegetable matter: add antifungal consideration if infiltrate; closer follow up at 24 hours.
• Review at 24 hours (and 2 to 3 days for rust rings or deep foreign bodies); refer immediately if penetration, deep stromal foreign body, infection, retained fragments, or unresolved defect.
• Advise protective eyewear for work.
• Tetanus prophylaxis if status inadequate and injury is dirty.