What is the appropriate initial assessment for a corneal abrasion?

Initial Assessment of Corneal Abrasion

For any patient presenting with suspected corneal abrasion, perform fluorescein staining with cobalt blue light examination to confirm the diagnosis—the abrasion will appear green under blue light and yellow under white light. 1, 2

Essential History Elements

• Mechanism of injury: Specifically ask about contact lens wear (highest risk factor in the U.S.), high-velocity projectiles, organic material (wood, plant matter), metal grinding, or chemical exposure 3, 2
• Timing: Document exact time of injury—prophylactic antibiotics are most effective when started within 24 hours 1, 3
• Contact lens history: Overnight wear, overwear beyond FDA-approved replacement, inadequate disinfection, contaminated storage cases, swimming/hot tub use while wearing lenses 1
• Prior corneal surgery: Refractive surgery, cataract surgery, glaucoma surgery, or keratoplasty significantly increases infection risk 1
• Immunosuppression or diabetes: These conditions affect healing and increase infection risk 3, 2

Critical Physical Examination Components

Visual Acuity

• Measure and document visual acuity with current correction before any other examination 4

Slit-Lamp Biomicroscopy

• Examine eyelid margins and lashes for foreign bodies, particularly under the upper lid—a linear pattern of abrasion indicates a retained foreign body 4, 5
• Assess corneal epithelium with fluorescein staining: document size, shape, depth (by staining intensity), and location (central vs. peripheral) 4, 5
• Differentiate pooling from staining: Fluorescein pooling in areas of corneal thinning must be distinguished from actual epithelial defects 5
• Evaluate for stromal infiltrates: Any white opacity, suppuration, necrosis, or feathery margins suggests bacterial keratitis rather than simple abrasion 1, 5
• Check anterior chamber: Look for cells, flare, or hypopyon (layered white cells)—hypopyon signals severe infection requiring immediate ophthalmology referral 1, 5

Pupillary Examination

• Assess pupil size, shape, and reactivity: An irregular pupil after trauma suggests penetrating injury requiring emergent referral 3

Intraocular Pressure

• Defer contact tonometry in the setting of suspected infection or corneal trauma 4

Red Flags Requiring Immediate Ophthalmology Referral

• High-velocity injury or penetrating trauma 3
• Irregular pupil after trauma 3
• Eye bleeding or acute vision loss 3
• Central infiltrate >2mm (requires cultures before antibiotic initiation) 1, 3
• Deep stromal involvement, corneal melting, or hypopyon 1, 3, 5
• Corneal infiltrate with suppuration, necrosis, or feathery margins 1, 3

Risk Stratification for Treatment Planning

High-Risk Features (Require Antipseudomonal Coverage)

• Contact lens wear (especially overnight wear) 1, 3
• Contaminated trauma (organic material, soil, water exposure) 1
• Prior corneal surgery 1, 3
• Immunosuppression or diabetes 3
• Chronic ocular surface disease (severe dry eye, entropion, lagophthalmos) 1

Standard-Risk Features

• Simple mechanical trauma without the above risk factors 3, 2
• Small abrasion (≤4mm) with normal vision and no infiltrate 2

Common Pitfalls to Avoid

• Do not miss a retained foreign body: Always evert the upper eyelid and examine carefully—linear abrasions are pathognomonic 5, 2
• Do not confuse fluorescein pooling with epithelial defects: Pooling occurs in areas of thinning without actual epithelial loss 5
• Do not overlook anterior chamber reaction: More significant abrasions can cause anterior chamber inflammation 5
• Do not delay treatment: Antibiotic prophylaxis prevents ulceration only when started within 24 hours of injury 1, 3