Is it safe to inject a quinolone (fluoroquinolone) antibiotic into the eyeball during glaucoma surgery?

Intraocular Quinolone Injection During Glaucoma Surgery

No, quinolone antibiotics should not be routinely injected into the eyeball during glaucoma surgery—current guidelines do not recommend antibiotic prophylaxis for closed globe glaucoma procedures, and when prophylaxis is indicated for open eye surgeries, cefuroxime (not a quinolone) is the preferred intracameral agent. 1

Guideline-Based Recommendations for Glaucoma Surgery

Closed Globe Glaucoma Procedures

• No antibiotic prophylaxis is recommended for closed globe surgeries, which includes most glaucoma procedures 1
• This guideline applies to procedures that do not involve opening the anterior chamber 1

Open Eye Glaucoma Surgery (e.g., Trabeculectomy)

When glaucoma surgery involves opening the eye and meets criteria for "open eye surgery with risk factors," the recommended approach is:

• Oral levofloxacin (a quinolone): 500 mg taken 12 hours before surgery, then 500 mg taken 2-4 hours before surgery 1
• NOT intracameral or intravitreal quinolone injection 1

Preferred Intracameral Agent (When Indicated)

• Cefuroxime 1 mg in 0.1 mL injected into the anterior chamber at the end of the procedure is the approved intracameral antibiotic for cataract surgery and has been the standard since 2014 1
• This is a cephalosporin, not a quinolone 1, 2

Safety Concerns with Intracameral Quinolones

Documented Toxicity Risks

While quinolones can be used intracamerally in specific circumstances, significant safety concerns exist:

• Retinal toxicity is dose-dependent and has been documented with fluoroquinolones 3
• Safe intracameral doses are extremely limited: ciprofloxacin <25 μg, with intravitreal doses of ciprofloxacin 100 μg, ofloxacin 50 μg/mL, and moxifloxacin ≤160 μg/0.1 mL considered safe 3
• Corneal precipitation occurs particularly with ciprofloxacin and norfloxacin, potentially delaying healing and resulting in corneal perforation in approximately 10% of cases 3

Comparative Safety: Cefuroxime Toxicity

Even the preferred agent (cefuroxime) carries risks when dosing errors occur:

• A case report documented severe retinal toxicity when cefuroxime 12.5 mg/0.1 mL (instead of the standard 1 mg/0.1 mL) was inadvertently injected intracamerally during trabeculectomy 4
• The patient developed uveitis, vitritis, serous macular detachment, and outer retinal changes requiring intensive corticosteroid therapy 4
• This emphasizes the critical importance of correct dosing and administration routes 4

Rationale for Avoiding Quinolone Overuse

Resistance Preservation

• Topical fluoroquinolones are not recommended for prophylaxis in order to preserve their antibacterial activity for curative treatment of severe eye infections 2
• Resistance to quinolones may not reverse with drug withdrawal, emphasizing the importance of prudent prescribing 5
• Increasing fluoroquinolone resistance has been documented, with methicillin-resistant staphylococcal isolates showing 42% prevalence and high concurrent fluoroquinolone resistance 1

Appropriate Quinolone Use in Ophthalmology

Fluoroquinolones are appropriately used:

• Topically for bacterial keratitis treatment (not prophylaxis), where they achieve therapeutic corneal concentrations 1, 5
• Orally for open eye surgery prophylaxis when risk factors are present 1
• Systemically or intravitreally for endophthalmitis treatment at carefully controlled doses 5, 3

Common Pitfalls to Avoid

• Do not inject quinolones intracamerally during routine glaucoma surgery—this is not guideline-supported and carries unnecessary toxicity risks 1, 3
• Do not confuse prophylaxis protocols between cataract surgery (intracameral cefuroxime indicated) and glaucoma surgery (typically no prophylaxis needed) 1
• Ensure correct drug concentration and route if any intracameral injection is performed, as dosing errors can cause severe retinal toxicity 4
• Avoid topical fluoroquinolone prophylaxis to preserve these agents for therapeutic use 2