What is the best antibiotic for treating a corneal abrasion?

Best Antibiotic for Corneal Abrasion

Fourth-generation fluoroquinolones (moxifloxacin 0.5% or gatifloxacin 0.5%) applied four times daily are the preferred topical antibiotics for corneal abrasion, offering superior gram-positive coverage compared to earlier fluoroquinolones while maintaining broad-spectrum efficacy. 1, 2

Standard Treatment Algorithm

First-Line Antibiotic Selection

• Apply moxifloxacin 0.5% or gatifloxacin 0.5% eye drops four times daily until complete epithelial healing occurs 1, 2

• These fourth-generation fluoroquinolones provide better coverage of gram-positive pathogens (including Staphylococcus aureus and Streptococcus pneumoniae) than earlier generation fluoroquinolones while maintaining excellent gram-negative coverage 2

• Gatifloxacin demonstrated 90% microbiological eradication rates in clinical trials versus 70% for vehicle control 3

• Initiate treatment within 24 hours of the abrasion to prevent ulceration 1, 2

Alternative Options

• Levofloxacin 1.5% provides equivalent efficacy to ofloxacin with the advantage of higher concentration 1

• Ofloxacin 0.3% is an acceptable alternative fluoroquinolone option 1

• Topical antibiotic eye drops are strongly preferred over ointments because drops achieve significantly higher tissue levels in the cornea 1

Role of Tetracycline Ointment (Limited)

• Tetracycline ointment lacks adequate corneal penetration due to poor solubility and should not be used as monotherapy 1

• May be useful only at bedtime as adjunctive therapy to antibiotic drops in less severe cases 1

Special Populations Requiring Modified Approach

Contact Lens-Related Abrasions (High Risk)

• Must prescribe antipseudomonal coverage due to increased risk of Pseudomonas aeruginosa keratitis 1, 4

• Use fourth-generation fluoroquinolones (moxifloxacin or gatifloxacin) which provide adequate Pseudomonas coverage 2

• Never patch the eye or use therapeutic contact lenses in contact lens wearers as this significantly increases bacterial keratitis risk 1, 2

Metal or Contaminated Trauma

• Fourth-generation fluoroquinolones (moxifloxacin or gatifloxacin) remain first-line due to broad-spectrum coverage 2

• Apply four times daily until complete re-epithelialization 2

Treatment Escalation for Severe Cases

Indications for Aggressive Treatment

• Immediately escalate if the abrasion progresses to bacterial keratitis with any of the following: 1
  • Central location or infiltrate >2mm
  • Deep stromal involvement
  • Presence of hypopyon
  • Corneal stromal loss

Escalated Regimen

• Initiate loading dose every 5-15 minutes, then hourly dosing 1

• Consider fortified antibiotics (tobramycin 1.5% + cefazolin 10%) prepared by FDA-designated 503A/503B compounding pharmacy for severe keratitis 1

• Fourth-generation fluoroquinolones have demonstrated at least equivalent efficacy to fortified cefazolin/tobramycin combination therapy 1

Critical Pitfalls to Avoid

Steroid Use

• Never use combination steroid-antibiotic drops as initial therapy 1

• Steroids should only be added after 2-3 days of antibiotic-only therapy and only after infection has been ruled out 1, 2

• Steroids can mask signs of infection and worsen outcomes 2

Patching and Contact Lenses

• Do not patch the eye as this does not improve pain and may delay healing 1, 4

• Avoid therapeutic contact lenses, particularly in contact lens-associated abrasions, due to increased bacterial keratitis risk 1, 2

Antibiotic Resistance Concerns

• Increasing resistance to fluoroquinolones has been observed, particularly with MRSA and Pseudomonas aeruginosa 2

• Chronic prophylactic antibiotic use may promote resistant organism growth 1

• Despite resistance concerns, prophylactic antibiotics remain recommended when started within 24 hours 1, 2

Follow-Up Requirements

• Small abrasions (≤4mm) with normal vision and resolving symptoms may not require follow-up 4

• All other patients require reevaluation within 24 hours 1

• If no improvement after 7 days, reevaluate diagnosis and treatment 2

• Monitor for signs of infection: increasing pain, purulent discharge, corneal infiltrate 1

Evidence Quality Note

While the American Academy of Ophthalmology strongly recommends topical antibiotics for corneal abrasion prophylaxis 1, 2, a 2025 Cochrane review found very low certainty evidence regarding antibiotic efficacy, with one study paradoxically showing increased infection risk with antibiotics versus placebo 5. However, given the potential sight-threatening consequences of bacterial keratitis and the established clinical practice supported by professional guidelines, fluoroquinolone prophylaxis remains the standard of care when initiated within 24 hours of injury 1, 2.