01OverviewDefinition, clinical context and the essential points that orientate the chapter.
The corneal epithelium is a thin protective layer over a densely innervated transparent surface. A small scratch may therefore cause disproportionate pain, watering, photophobia and an inability to keep the eye open. Common causes include a fingernail, a plant branch, rubbing after windblown debris or contact-lens handling. Most simple defects heal rapidly, but the term abrasion should be used only after considering how the injury occurred and whether the findings fit a superficial wound. A history of metal striking metal changes the assessment even when the visible mark is small.
Start with visual acuity, then inspect the lids, conjunctiva, corneal clarity, pupil shape and anterior chamber without pressing on the globe. A shallow chamber, peaked pupil, obvious laceration or prolapsed dark tissue is incompatible with an uncomplicated scratch. Fluorescein seen under blue light outlines epithelial loss. Streaming of clear fluid through fluorescein suggests an aqueous leak, but a sealed entry wound can give a negative Seidel test. Do not pursue the test by manipulating a clinically obvious open globe. Absence of visible debris does not exclude an intraocular fragment after a high-energy mechanism.
The upper tarsal surface can retain a particle that repeatedly scrapes the cornea during blinking. Several vertical linear defects are a useful clue. After excluding concern about penetration, evert the lid and inspect systematically. A superficial loose particle can often be removed with irrigation or a moistened sterile applicator. Needles and burrs require training, slit-lamp magnification and a cooperative patient; they are not appropriate improvised tools. Central, deeply embedded or organic material, a significant rust ring, or an unsuccessful attempt should lead to specialist removal rather than repeated scraping.
Contact-lens wear introduces a separate infection concern. Pain and redness may be attributed to difficult lens removal when the underlying problem is microbial keratitis. A focal white stromal infiltrate, increasing pain, discharge, anterior chamber reaction or reduced acuity raises the concern substantially. Chloramphenicol used for a simple scratch is not a sufficient treatment plan for suspected contact-lens-related infection. Keep the lenses out, obtain urgent ophthalmology assessment and follow the specialist antimicrobial pathway. Retain lens information and, if requested, the lenses and case for microbiological investigation.
Treatment for a genuinely uncomplicated abrasion aims to control symptoms, prevent secondary infection where indicated and support epithelial repair. The cited Moorfields pathway uses chloramphenicol 1% ointment four times daily for five days. This is an NHS trauma regimen; the cited manufacturer's product is licensed for acute bacterial conjunctivitis, so abrasion prophylaxis is off-label. Oral analgesia can be chosen according to the person's contraindications. Routine pressure patching does not reliably improve healing and may conceal deterioration. A therapeutic bandage contact lens is a specialist treatment with infection precautions and review, not permission to resume ordinary contact-lens wear.
Persistent or recurrent symptoms require a fresh explanation. A retained particle, developing infection, a dendritic lesion or recurrent epithelial erosion can mimic failure of an ordinary scratch to settle. Recurrent erosion often causes pain on opening the eye after sleep because the epithelium adheres poorly to the underlying surface. Ask about previous similar episodes and old fingernail injuries. A central scar can affect vision even after the defect closes, and repeated injuries should prompt practical advice on eye protection that fits the person's actual work.
Key points
- Check the mechanism before calling an injury superficial: grinding, hammering or mowing can propel a fragment through a tiny entry wound.
- Record visual acuity in each eye, examine the pupils and anterior chamber, and use fluorescein to define the epithelial defect.
- Vertical scratches suggest material beneath the upper lid; evert the lid only when examination has excluded a suspected open globe.
- Loose superficial debris may be irrigated or gently removed by a competent clinician; embedded, central or deep material requires appropriate magnification and expertise.
- An NHS specialist regimen for an uncomplicated abrasion is chloramphenicol 1% eye ointment four times daily for five days; trauma prophylaxis is outside the conjunctivitis licence of the cited product.
- Do not use routine pressure patching or provide repeated unsupervised topical anaesthetic; contact lenses remain out until healing and clinician clearance.
- Increasing pain, redness, discharge or reduced vision needs earlier review; incomplete healing should prompt reassessment of the diagnosis.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Direct epithelial trauma
Fingernails, paper edges, branches and other small objects can shear the corneal epithelium without breaching the full thickness of the eye wall.
Environmental particles
Dust, grit and metallic fragments can lodge on the cornea or tarsal conjunctiva; organic matter carries additional microbial contamination risk.
Lens-related surface injury
Lens insertion, removal, poor fit or a damaged lens can disrupt the epithelium, while lens wear also increases susceptibility to microbial keratitis.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Exposed sensory endings
Loss of epithelial coverage exposes a richly innervated surface, producing marked pain, reflex tearing and blepharospasm even when the defect is relatively small.
- 2Repeated mechanical scraping
A particle trapped under an eyelid moves over the cornea during blinking, creating repeated epithelial trauma and characteristic linear staining tracks.
- 3Defective epithelial adhesion
After some injuries, new epithelium attaches weakly to its basement membrane and can detach again when the eyelid opens, causing recurrent erosion.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Sudden pain, tearing and photophobia follow a minor mechanical event, with a fluorescein-positive defect and no infiltrate, pupil distortion or unexplained visual reduction.
Persistent scratching with blinking and vertical corneal staining tracks suggest a particle concealed beneath the upper eyelid rather than an isolated one-off abrasion.
A corneal white spot, worsening redness or increasing discomfort in a contact-lens wearer demands urgent assessment for infection even when a scratch was reported.
Power-tool use, metal hammering, an abnormal chamber or an irregular pupil should trigger protection and specialist assessment before any attempt at routine removal.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Visual acuity and mechanism assessmentFirst step - Why
- Identify functional loss and whether high-energy penetration is plausible.
- Interpretation and limitations
- Measure each eye and compare with previous vision where known; a central abrasion can blur sight, but major unexplained loss needs investigation beyond the visible scratch.
- 02
Fluorescein with appropriate illumination - Why
- Locate epithelial loss and distinguish focal scratches from alternative patterns.
- Interpretation and limitations
- Look for linear tracks, a branching lesion or leakage; a negative leak test does not exclude a sealed penetrating injury.
- 03
Magnified inspection and safe lid eversion - Why
- Find retained material and assess its depth and location.
- Interpretation and limitations
- Evert only when open-globe injury is not suspected, and stop removal attempts if the foreign body is deep, central or beyond available competence.
- 04
Selective orbital imaging or corneal microbiology - Why
- Investigate suspected internal foreign material or sight-threatening corneal infection.
- Interpretation and limitations
- Ophthalmology may request CT for high-velocity fragments or corneal sampling for keratitis; neither is routine for a clearly uncomplicated small abrasion.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Infectious corneal ulcer
Microbial invasion produces a stromal infiltrate with epithelial loss; contact-lens wear, contaminated trauma and worsening symptoms increase its likelihood.
Herpes simplex keratitis
A branching epithelial lesion can present with pain and staining but differs from a simple traumatic defect in its morphology and recurrent disease pattern.
Penetrating ocular injury
A full-thickness entry wound may be tiny or temporarily sealed, while an internal fragment or abnormal pupil indicates damage beyond a superficial abrasion.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01Safety assessmentDecide whether the injury is superficialFirst stepA person presents with a painful watering eye after trauma or a suspected foreign body.+
- 1Record the event, contact-lens use and acuity, inspecting for pupil or anterior chamber abnormalities and corneal infiltration before manipulating the surface.
- 2If penetration is plausible, apply a rigid protective shield without pressure and arrange emergency ophthalmology assessment rather than attempting office removal.
- 3If an infiltrate or suspicious contact-lens presentation is found, refer urgently for corneal assessment and targeted treatment instead of using the uncomplicated abrasion pathway.
02Superficial foreign materialRemove only what can be removed safelyExamination identifies a loose superficial particle without evidence of penetration or significant infection.+
- 1Use brief clinician-administered topical anaesthesia when needed, then irrigate or remove loose material gently with an appropriate moistened applicator.
- 2Inspect the cornea and beneath the upper lid, checking that the foreign body is completely removed and that no significant residual rust or deeper defect remains.
- 3Refer embedded, central, difficult or incompletely removed material to the eye service, documenting attempts so further manipulation can be planned safely.
03Abrasion careSupport healing with explicit reviewA simple epithelial defect remains after serious injury and retained material have been excluded.+
- 1Provide the selected topical antimicrobial regimen when appropriate, oral pain relief and advice to avoid rubbing or contact-lens wear during healing.
- 2Explain the expected improvement and arrange review according to defect size, location, acuity, infection risk and reliability of access to care.
- 3Reassess promptly for worsening symptoms or failure to improve within twenty-four to forty-eight hours, rather than repeatedly extending empirical treatment.
Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
Chloramphenicol 1% eye ointment
Apply an approximately 1 cm ribbon to the affected eye four times daily for five days under the cited Moorfields abrasion protocol.Abrasion prophylaxis is off-label for the cited conjunctivitis product. Check allergy and personal or family blood-dyscrasia history; suspected contact-lens keratitis requires different specialist-directed cover.
Proxymetacaine 0.5% procedural eye drops
Instil one or two drops topically immediately before suitable superficial foreign-body removal by a trained clinician, then stop procedural use.Repeated unsupervised use can delay recognition of infection and cause serious corneal toxicity; do not send the patient home with a bottle for unrestricted analgesia.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Secondary corneal infection
The epithelial barrier defect permits microbial entry, potentially causing an ulcer, tissue destruction and lasting visual loss if infection progresses.
Corneal scarring
Deeper injury or inflammation can leave an opacity whose visual effect depends on its density and proximity to the central optical axis.
Recurrent epithelial erosion
Poor adhesion after healing can lead to repeated painful episodes, often on waking, despite the absence of a new external injury.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Record the defect and visual acuity at review so that improvement is demonstrable rather than inferred only from reduced discomfort.
- Arrange closer follow-up for large or central defects, contact-lens-related injury, residual rust, incomplete removal or difficulty administering treatment.
- Escalate increasing pain, discharge, redness or deteriorating vision immediately because infection can develop before the planned review.
- Check that symptoms have resolved before ordinary lens wear resumes and discuss recurrence on waking as a reason for further corneal assessment.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
Mechanism can outweigh appearance
A tiny wound from a fast metal fragment may conceal much greater internal damage than a broad but superficial epithelial scratch.
Anaesthetic relief has limits
Pain relief after a topical anaesthetic suggests a surface contribution but does not prove that no serious injury or infection exists.
A rust ring needs judgement
Residual iron staining can require specialist removal, particularly near the visual axis; repeated forceful attempts can enlarge the defect and scar the cornea.
Protection should fit the task
Appropriate wraparound industrial eye protection reduces recurrent injury from grinding and drilling more effectively than relying on ordinary spectacles alone.
11Common pitfallsFrequent interpretation and management errors.
- 01
Labelling every contact-lens-associated painful eye an abrasion without examining for a corneal infiltrate.
- 02
Using an untrained needle technique to remove an embedded particle because it appears small.
- 03
Assuming a negative Seidel test excludes an intraocular foreign body after high-velocity injury.
- 04
Repeating anaesthetic drops at home or applying a tight patch that delays recognition of worsening disease.