Conjunctival Foreign Body

Conjunctival foreign bodies are common, usually minor injuries caused by dust, sand, wood, insects, metal fragments, eyelashes or vegetable matter.

• Most lodge in the subtarsal sulcus of the upper lid (a groove about 2 mm from the lid margin), causing linear corneal abrasions on blinking.
• Others embed in the bulbar conjunctiva or fornices.
• Hot or high velocity particles (grinding, hammering, explosions) may penetrate the globe, so always consider intraocular foreign body.
• Occupational exposure and lack of protective eyewear are common risk factors.

• Foreign body sensation, tearing, redness, discomfort worse on blinking, photophobia.
• Visible foreign body on the conjunctiva; vertical linear corneal abrasions (superficial punctate or "ice rink" pattern) suggest a subtarsal foreign body.
• Mild chemosis and injection, localised.
• Vegetable matter or organic material carry infection risk (fungal keratitis), and copper or iron cause toxicity (siderosis, chalcosis).
• Red flags: reduced vision, severe pain, history of high velocity injury, irregular pupil, hyphaema, positive Seidel test, lowered intraocular pressure, which suggest globe penetration.

• History: mechanism, particle type, speed, protective eyewear use.
• Visual acuity before treatment. Slit lamp examination with fluorescein.
• Evert the upper lid (and use a double eversion with a Desmarres retractor for the fornix) and sweep the fornices.
• Dilated fundus examination to exclude posterior segment injury if there is a high velocity mechanism.
• CT orbits (thin cuts) if intraocular or intraorbital foreign body suspected; avoid MRI with possible metallic foreign body.

• Instil topical anaesthetic (proxymetacaine 0.5 percent or tetracaine 1 percent).
• Remove superficial foreign bodies with irrigation using saline, or with a moistened cotton bud or fine forceps at the slit lamp. Deeply embedded: remove with a 25 or 27 gauge needle bevel up, or with microforceps.
• Evert the lid and wipe the sulcus with a sterile cotton bud; irrigate fornices.
• Post removal: topical antibiotic ointment (chloramphenicol 1 percent ointment or erythromycin 0.5 percent ointment) four times daily for 3 to 5 days if there is an epithelial defect; lubricants. No patching is required.
• Do not prescribe topical anaesthetic to take home (delays healing and causes toxicity).
• Tetanus prophylaxis if the injury is contaminated and immunisation status is not current.
• Embedded vegetable matter: exclude fungal infection; review within 24 to 48 hours.
• Suspected penetration: shield the eye, avoid pressure, keep nil by mouth, systemic antibiotics (levofloxacin 750 mg orally or intravenously), refer for urgent exploration.
• Counsel on eye protection; follow up at 24 to 48 hours for large abrasions.