Corneal Abrasion: The Common Injury With Two Dangerous Mistakes

The most common eye injury in any emergency department is also one of the easiest to mismanage in ways that cost a patient their cornea.

A corneal abrasion is a defect in the corneal epithelium, and most heal completely within a couple of days.

That reliability is exactly what makes the exceptions dangerous.

A contact lens wearer, an organic-matter injury, or a retained foreign body under the upper lid each turn a trivial injury into a sight-threatening one.

Two management errors – patching a high-risk eye and sending the patient home with topical anaesthetic – can convert a self-limiting abrasion into an ulcer.

Knowing which abrasions are routine, which are not, and what never to prescribe is the whole of safe management.

What Is a Corneal Abrasion?

A corneal abrasion is a traumatic or mechanical disruption of the corneal epithelium, without penetration of Bowman layer or the underlying stroma.

Abrasions are usefully grouped by mechanism, because mechanism drives risk:

Simple traumatic abrasion – fingernails, paper edges, make-up brushes and similar direct trauma
Foreign body-related abrasion – from a particle that has since been removed or is still present
Contact lens-related abrasion – carrying a materially higher risk of infection, including Pseudomonas
Organic-matter abrasion – from vegetable matter, soil or animal material, with a real risk of fungal keratitis
Recurrent erosion – a spontaneous breakdown at the site of a previous abrasion, often on waking

The cornea is one of the most densely innervated tissues in the body, which is why a superficial epithelial defect produces pain out of all proportion to its depth.

Epidemiology

Corneal abrasion is among the most frequent ocular presentations in acute care.

It is one of the commonest eye complaints in emergency departments and primary care
Occupational injury accounts for a substantial share, particularly in manual and industrial work without eye protection
Contact lens wearers form a distinct and higher-risk group
Young children present with abrasions from fingernails and toys, often with nothing more than inconsolable crying and lid closure

Because the great majority resolve rapidly and uneventfully, the clinical skill lies in reliably identifying the minority that will not.

Pathophysiology

Corneal epithelium has a remarkable capacity for rapid repair, which explains the usual course.

Mechanical injury strips epithelial cells, exposing the richly innervated subepithelial nerve plexus and producing intense pain
Adjacent epithelial cells slide across the defect within hours to cover it
Limbal stem cells then supply new cells, and the epithelium restratifies over the following days
An intact epithelium is the cornea’s principal barrier to infection, so while the defect is open the stroma is vulnerable to microbial invasion
Where the injury damages the epithelial basement membrane, the new epithelium may adhere poorly – the basis of recurrent corneal erosion

This is why the two things that matter most in management are speed of re-epithelialisation and preventing infection while the barrier is down.

Risk Factors

Higher-Risk Mechanisms

Contact lens wear, especially overnight wear or poor hygiene
Injury by organic material – branches, leaves, soil, animal matter
Grinding, hammering or drilling without eye protection, which raises the possibility of a penetrating injury rather than a simple abrasion
Any suggestion of a high-velocity projectile

Patient-Related Risk Factors

Dry eye disease and epithelial basement membrane dystrophy, which predispose to recurrent erosion
Diabetes mellitus, associated with delayed epithelial healing
Reduced corneal sensation from any cause, which blunts the protective pain response
Previous corneal surgery or a prior abrasion at the same site

The history essentially triages the patient: a fingernail injury and a hammer-and-chisel injury with the same fluorescein appearance are not the same clinical problem.

Clinical Presentation

Symptoms

Sudden, severe eye pain and a sharp foreign-body sensation
Marked photophobia, tearing and blepharospasm
Blurred vision when the defect involves the visual axis
A clear history of a precipitating event in most cases, although not all patients recall one
In young children, unexplained crying, lid closure and reluctance to open the eye

Examination Findings

An epithelial defect staining bright green with fluorescein under cobalt blue light
Conjunctival injection and reflex tearing
A clear underlying stroma – any white infiltrate beneath or around the defect suggests infection rather than a simple abrasion
Vertical linear abrasions, which strongly suggest a retained foreign body under the upper lid
Normal anterior chamber; cells and flare or a hypopyon indicate a more serious process

Everting the upper eyelid is not optional – vertical “ice-rink” scratch lines mean a foreign body is still there, and the abrasion will not heal until it is removed.

Diagnostic Evaluation

Examination

Visual acuity before anything else, including after topical anaesthetic if the patient cannot open the eye
Fluorescein staining with cobalt blue illumination to define the defect
Double eversion of the upper lid and sweeping of the fornices to exclude a retained foreign body
Assessment of the anterior chamber for cells, flare or hypopyon

Excluding a Penetrating Injury

A Seidel test where the mechanism raises any suspicion of perforation
Assessment for a peaked pupil, shallow anterior chamber or subconjunctival haemorrhage covering the sclera
Imaging to exclude an intraocular foreign body after high-velocity injury, particularly hammering metal on metal

When to Culture

Corneal scrape and culture where there is an infiltrate, significant anterior chamber reaction, or a contact lens-related presentation that is not behaving like a simple abrasion

A high-velocity mechanical injury deserves imaging even when the cornea looks unimpressive, because a self-sealing entry wound can look exactly like an abrasion.

Differential Diagnosis

Conditions that can present similarly include:

Microbial keratitis – an infiltrate under the defect, worsening rather than improving pain, and often anterior chamber activity
Herpes simplex epithelial keratitis – a branching dendrite with terminal bulbs rather than a plain defect, often with reduced corneal sensation
Recurrent corneal erosion – spontaneous pain on waking, typically at the site of an old injury
Ultraviolet photokeratitis – bilateral diffuse punctate staining after welding or intense UV exposure
Corneal foreign body still in situ – the abrasion is a consequence, not the whole diagnosis
Penetrating injury – the diagnosis that must never be mistaken for an abrasion

The single most useful rule is that an abrasion should be markedly better within 24 to 48 hours; one that is worse is being treated as the wrong diagnosis.

Management

Standard Treatment

Topical antibiotic prophylaxis while the epithelial defect is open
Oral analgesia; some patients benefit from a short course of a topical NSAID
Cycloplegia for comfort where there is significant photophobia or ciliary spasm
Removal of any foreign body and, where present, its rust ring
Review within 24 to 48 hours, and sooner if symptoms worsen

What Not To Do

Never prescribe topical anaesthetic for home use – repeated use is toxic to the epithelium, blocks healing and can cause a devastating anaesthetic-abuse keratopathy
Do not patch a contact lens-related or organic-matter abrasion; patching creates a warm closed environment that favours infection, and evidence does not support patching for routine abrasions either
Do not use topical corticosteroids on an undiagnosed epithelial defect
Contact lens wear must stop until the epithelium has fully healed

Contact Lens Wearers and Organic Injury

Cover for Pseudomonas with an appropriate topical antibiotic and review closely
Maintain a low threshold for treating as presumed microbial keratitis rather than a simple abrasion
Consider fungal keratitis with organic-matter injury, particularly if healing stalls

The two prescribing errors above – take-home anaesthetic and patching the wrong eye – cause more harm in this condition than the original injury ever does.

Prognosis

The outlook for an uncomplicated abrasion is excellent.

Most small abrasions re-epithelialise within 24 to 72 hours with no visual consequence
Larger or central defects take longer and may leave transient blurring while the surface remodels
Recurrent erosion develops in a minority, particularly after a sharp injury such as a fingernail or paper cut, and can recur for months
Secondary microbial keratitis is the main sight-threatening complication and the reason for prophylaxis and prompt review

An abrasion that has not substantially improved by the follow-up visit should be reassessed as a possible infection or retained foreign body rather than simply given more time.

References

Wipperman JL, Dorsch JN. Evaluation and management of corneal abrasions. American Family Physician. 2013.
Lim CHL, Turner A, Lim BX. Patching for corneal abrasion. Cochrane Database of Systematic Reviews. 2016.
Yeung KK, Weissman BA. Contact lens-related complications and corneal infection risk. Clinical and Experimental Optometry.
Corneal Abrasion. StatPearls, NCBI Bookshelf.
American Academy of Ophthalmology. Corneal Abrasion and Corneal Foreign Body. EyeWiki.