What are the red flags for a patient presenting with a corneal abrasion, particularly those with a history of contact lens wear, recent eye surgery, pre-existing eye conditions such as glaucoma or uveitis, or compromised immune systems due to conditions like diabetes?

Red Flags in Corneal Abrasion

Contact lens wear is the single most critical red flag requiring aggressive antipseudomonal antibiotic coverage and avoidance of eye patching due to significantly elevated risk of bacterial keratitis, particularly from Pseudomonas aeruginosa. 1

High-Risk Patient Populations Requiring Immediate Escalation

Contact Lens-Related Abrasions

• Any contact lens wearer with corneal abrasion requires topical antibiotics with antipseudomonal coverage (fluoroquinolones preferred) 1, 2
• Overnight wear, overwear beyond FDA-approved replacement, inadequate disinfection, contaminated storage cases, and swimming/hot tub use while wearing lenses dramatically increase infection risk 1
• Never patch the eye in contact lens wearers - patching increases bacterial keratitis risk 1
• Bandage contact lens use remains controversial and should be avoided in this population 1

Recent Eye Surgery History

• Prior corneal surgery, refractive surgery, cataract surgery, glaucoma surgery, or keratoplasty significantly increases infection risk 1
• Loose corneal sutures present high risk for bacterial seeding 1
• These patients warrant cultures and smears even for smaller abrasions 1

Pre-existing Eye Conditions

• Glaucoma patients on topical medications have altered ocular surface defense mechanisms 1
• Uveitis or chronic anterior chamber inflammation requires cycloplegic agents to prevent synechia formation 1
• Neurotrophic keratopathy (trigeminal neuropathy, cranial nerve V/VII damage) delays healing and increases perforation risk 1
• Tear film deficiencies, eyelid abnormalities, or exposure keratopathy compromise epithelial healing 1

Immunocompromised States

• Diabetes mellitus is a major systemic risk factor for bacterial keratitis 1
• Critical illness, malnutrition, respirator dependence increase infection susceptibility 1
• Immunosuppression from medications or medical conditions (connective tissue disease, graft-versus-host disease) 1
• Atopic dermatitis/blepharoconjunctivitis, vitamin A deficiency 1

Clinical Features Requiring Cultures/Smears and Ophthalmology Referral

Size and Location Criteria

• Central infiltrate >2mm requires immediate cultures before antibiotic initiation 1
• Significant stromal involvement or corneal melting 1
• Multiple infiltrates in different corneal locations 1

Signs of Established Infection

• Corneal infiltrate with suppuration, necrosis, or feathery margins suggests bacterial keratitis 1
• Hypopyon (layered white cells in anterior chamber) 1, 2
• Substantial anterior chamber inflammation with cell and flare 1
• Endothelial plaque 1

Atypical Features Suggesting Non-Bacterial Pathogens

• Ring infiltrate pattern suggests Acanthamoeba (avoid corticosteroids) 1
• Satellite lesions suggest fungal infection (avoid corticosteroids) 1
• Crystalline appearance suggests Nocardia (avoid corticosteroids) 1
• History of trauma with vegetable matter raises fungal concern 1

Treatment Failure

• Chronic infection or unresponsive to 48 hours of broad-spectrum antibiotics mandates cultures 1
• Increasing pain, purulent discharge, or worsening infiltrate despite treatment 2, 3, 4

Trauma-Related Red Flags

Mechanism of Injury

• High-velocity injury or penetrating trauma requires immediate ophthalmology evaluation for possible globe rupture 2
• Metal grinding with foreign body and rust ring 5
• Chemical or thermal injury 1
• Contaminated trauma (soil, vegetable matter) increases fungal/bacterial risk 1

Associated Findings

• Irregular pupil after trauma suggests globe rupture or iris damage 2
• Eye bleeding or acute vision loss 2
• Full-thickness corneal involvement or perforation risk 1

Organism-Specific Resistance Patterns

• Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa show increasing resistance to fluoroquinolones 1
• Consider fortified antibiotics (tobramycin 1.5% + cefazolin 10%) for severe cases with these organisms 2
• Fourth-generation fluoroquinolones (moxifloxacin, gatifloxacin) demonstrate equivalent efficacy to fortified combinations 2

Critical Management Pitfalls to Avoid

• Never use corticosteroids in suspected Acanthamoeba, Nocardia, or fungal infections - they worsen outcomes 1
• Corticosteroids may only be considered after 24-48 hours when organism is identified and infection is responding 1
• Avoid topical anesthetics beyond initial examination - they delay healing 6
• Chronic prophylactic antibiotic use promotes resistant organisms 2, 3, 4
• Inadequate blinking or incomplete eyelid closure delays healing and may require temporary tarsorrhaphy 3

Follow-Up Requirements

• Contact lens wearers and high-risk patients require 24-hour follow-up to detect early infection 2, 3
• Simple abrasions in low-risk patients can be followed at 48-72 hours 6
• Healing typically occurs within 24-72 hours for uncomplicated abrasions 6
• Delayed healing (5-7 days) suggests underlying pathology requiring specialist evaluation 3