Describe the management of corneal abrasion and corneal foreign body.

Corneal Abrasion

• A corneal abrasion is a traumatic defect of the corneal epithelium without involvement of the deeper layers.
• It is one of the commonest of all ocular presentations and, correctly managed, heals within 24 to 48 hours without a scar.
• Causes — a fingernail (classically an infant’s), a leaf or twig, paper, a mascara brush, a contact lens, and after removal of a foreign body

Corneal Foreign Body

• History first, and it decides everything — the nature of the material, and above all whether it was travelling at high velocity: hammering metal on metal, grinding, chiselling, drilling or an explosion.
• Such a history raises the question of an intraocular foreign body → Record visual acuity in both eyes before doing anything — this is both clinical and medicolegal, since these are frequently industrial injuries → Examine at the slit lamp; stain with fluorescein; look for a SEIDEL test (a stream of aqueous diluting the fluorescein) indicating perforation; assess the anterior chamber depth and the pupil shape — a peaked pupil suggests iris incarceration in a wound → evert the upper lid, always, and double-evert if necessary; and sweep the fornices → If perforation is suspected: stop.
• Do not press on the eye, do not attempt removal, apply a shield (not a pad), keep the patient nil by mouth, give systemic antibiotic and tetanus prophylaxis, and arrange orbital CT — MRI is contraindicated if the material may be metallic → For a simple superficial foreign body: under topical anaesthesia at the slit lamp, remove with a sterile 26-gauge needle bevel-up or a foreign body spud, tangentially, moving away from the visual axis → Remove the rust ring with a battery-powered burr; if it is deep and central it may be left to migrate forward and be removed in a day or two rather than drilling into the visual axis → Antibiotic ointment, cycloplegic, and review at 24 to 48 hours

Applied Aspects

• Ask how the injury happened, and ask about hammering specifically; a high-velocity history changes a trivial-looking eye into a suspected penetrating injury
• Record the visual acuity of both eyes at presentation; it is the single most important entry in the notes and cannot be reconstructed later
• Evert the upper lid in every case; a retained subtarsal foreign body is the commonest reason an abrasion fails to heal, and linear vertical scratches point straight to it