Key Facts

Corneal abrasion is a superficial injury involving loss of the corneal epithelium. It is one of the most common eye injuries and causes significant pain due to the dense sensory innervation of the cornea. Most heal rapidly without sequelae.

Epidemiology

• Accounts for 10% of new eye casualty presentations
• Very common overall; exact incidence difficult to determine as many do not present
• Peak in young working-age adults
• Male predominance (occupational exposure)
• Common in contact lens wearers, children, and those with occupational exposure to foreign bodies

Aetiology

• Mechanical trauma: fingernail scratch (most common), tree branch, paper edge
• Foreign body: metallic, organic, or mineral particles
• Contact lens-related: over-wear, poor fitting, dry lens
• Occupational: grinding, welding, construction
• UV keratitis: welding flash ('arc eye'), snow blindness

Pathophysiology

• Loss of corneal epithelial cells exposes underlying nerve endings (corneal nerve plexus)
• Exposed nerve endings cause severe pain, reflex tearing, and blepharospasm
• Corneal epithelium regenerates rapidly (mitotic rate increases 5-8 fold after injury)
• Healing occurs by cell migration from limbal stem cells and adjacent epithelial cells
• Incomplete basement membrane regeneration predisposes to recurrent erosion syndrome

Typical Presentation

• Acute onset eye pain following injury
• Foreign body sensation
• Tearing (epiphora)
• Photophobia
• Blepharospasm (difficulty opening eye)
• Blurred vision (if central cornea involved)

Examination

• Visual acuity (may be mildly reduced if central)
• Fluorescein staining: bright green epithelial defect under cobalt blue light
• Examine for retained foreign body (evert upper lid)
• Note size, shape, and location of abrasion
• Vertical linear abrasions suggest subtarsal foreign body

Red Flags

• High-velocity injury (risk of penetrating injury)
• White corneal infiltrate (suggests infection/microbial keratitis)
• Hypopyon (indicates keratitis)
• Irregular pupil (suggests penetrating injury)
• Reduced visual acuity not improving with pinhole
• Contact lens wearer with corneal defect (risk of microbial keratitis — treat as keratitis)

Bedside

• Visual acuity (with correction)
• Slit lamp biomicroscopy with fluorescein staining and cobalt blue light
• Evert upper eyelid to exclude subtarsal foreign body
• Pupil examination (rule out penetrating injury — teardrop pupil)
• Intraocular pressure (may be difficult due to pain; defer if penetrating injury suspected)

Bloods

• Not required for simple corneal abrasion

Imaging

• Not usually required
• CT orbits if penetrating injury suspected (metallic intraocular foreign body)
• Do NOT perform MRI if metallic foreign body suspected

Special Tests

• Seidel test if penetrating injury suspected (fluorescein streaming indicates aqueous leak)
• Corneal sensation testing if HSV keratitis differential

Non-pharmacological

• Reassurance that most heal within 24-72 hours
• Avoid rubbing the eye
• Eye patches are NOT recommended (no benefit, may delay healing — Cochrane review)
• Wear sunglasses for photophobia
• Avoid contact lens wear until fully healed (plus 24 hours)

Pharmacological

• Chloramphenicol 1% ointment QDS for 5 days: prophylactic antibiotic (lubricating effect)
• OR Chloramphenicol 0.5% drops QDS + ointment at bedtime
• Topical anaesthetic (oxybuprocaine 0.4%, tetracaine 1%): for examination only, NEVER prescribe for home use (delays healing, causes corneal toxicity)
• Cyclopentolate 1% single dose: for severe pain from ciliary spasm
• Oral analgesia: paracetamol 1g QDS ± ibuprofen 400mg TDS

Surgical

• Foreign body removal with slit lamp and needle/burr under topical anaesthesia
• Rust ring removal with rotary burr

Referral Criteria

• Ophthalmology referral if: large central abrasion, white infiltrate, penetrating injury suspected, not healing after 48-72 hours, contact lens-related (manage as possible keratitis)
• Recurrent erosion syndrome: ophthalmology for lubricants, anterior stromal puncture, or phototherapeutic keratectomy

• >95% of simple abrasions heal within 24-72 hours
• No residual visual deficit for peripheral abrasions
• Central corneal abrasions may leave faint scar affecting vision
• Recurrent erosion syndrome: occurs in 5-10%, especially with fingernail injuries; may recur for months to years
• UV keratitis resolves within 24-48 hours with supportive care
• Complications (rare): secondary infection, corneal scarring, recurrent erosion syndrome

Recurrent Corneal Erosion Syndrome

Key Principles of Corneal Abrasion Management