Recommended Eye Drops for Bacterial Conjunctivitis
For uncomplicated bacterial conjunctivitis, use topical moxifloxacin 0.5% three times daily for 5-7 days as the first-line treatment. 1, 2
First-Line Treatment: Fourth-Generation Fluoroquinolones
Moxifloxacin 0.5% is the preferred topical antibiotic because it provides superior gram-positive coverage including activity against some methicillin-resistant Staphylococcus aureus strains, and achieves complete resolution in 81% of patients by 48 hours. 1, 3, 4
Dosing Regimen
- Moxifloxacin 0.5%: Instill one drop in the affected eye three times daily for 7 days 2
- Alternative fourth-generation option: Gatifloxacin 0.5% - Day 1: one drop every 2 hours while awake (up to 8 times); Days 2-7: one drop 2-4 times daily 5
Why Moxifloxacin is Superior
Moxifloxacin demonstrates significantly faster clinical cure compared to older agents, with 81% complete resolution at 48 hours versus 44% with polymyxin B/trimethoprim (P=0.001). 3 It achieves microbiological eradication rates of 84-94% against the three principal pathogens: Haemophilus influenzae (98.5%), Streptococcus pneumoniae (86.4%), and Staphylococcus aureus (94.1%). 1, 6
Alternative First-Line Options
When fourth-generation fluoroquinolones are unavailable or cost-prohibitive, the following are acceptable alternatives:
- Ofloxacin 0.3%: Four times daily for 5-7 days 1
- Ciprofloxacin: One to two drops every 2 hours while awake for 2 days, then every 4 hours while awake for 5 days 7
- Gentamicin, tobramycin, or azithromycin: Endorsed by WHO as appropriate alternatives 1, 8
Important caveat: No clinical evidence demonstrates superiority of any specific topical antibiotic over another for mild cases, so choice can be based on dosing convenience, cost, and local resistance patterns. 1, 9
Special Circumstances Requiring Different Management
Contact Lens Wearers
Reserve fluoroquinolones (ofloxacin or ciprofloxacin) for contact lens wearers due to higher risk of Pseudomonas infection. 9 Advise patients not to wear contact lenses during treatment. 2
Suspected MRSA Conjunctivitis
Consider compounded topical vancomycin, as MRSA isolates are generally resistant to fluoroquinolones and aminoglycosides but susceptible to vancomycin. 1, 9 MRSA should be suspected in patients from nursing homes or with community-acquired infections. 1
Gonococcal Conjunctivitis (Severe Purulent Discharge)
Topical antibiotics alone are insufficient. 1, 9 Requires:
- Systemic therapy: Ceftriaxone 250 mg IM single dose PLUS azithromycin 1 g oral single dose 1
- Obtain conjunctival cultures and Gram staining before initiating treatment 1, 9
- Daily monitoring until resolution 1
- Critical pitfall: Delayed referral can lead to corneal perforation and vision loss 1
Chlamydial Conjunctivitis
Systemic antibiotics are mandatory, as topical therapy alone is insufficient and >50% of infants have concurrent infection at other sites. 1, 9
- Adults: Azithromycin 1 g oral single dose OR doxycycline 100 mg oral twice daily for 7 days 1
- Neonates: Erythromycin base or ethylsuccinate 50 mg/kg/day oral divided into 4 doses for 14 days 1, 9
- Treat sexual partners and consider sexual abuse in children 1
When to Avoid Topical Antibiotics
Do NOT use topical antibiotics for viral conjunctivitis, as they provide no benefit, cause potential adverse effects, and promote antibiotic resistance. 1 Viral conjunctivitis requires only supportive care with artificial tears, cold compresses, and topical antihistamines for symptom relief. 1
Red Flags Requiring Immediate Ophthalmology Referral
Refer urgently if any of the following are present: 1, 9
- Visual loss
- Moderate or severe pain
- Severe purulent discharge (suspect gonococcal)
- Corneal involvement (infiltrate, ulcer, opacity)
- Conjunctival scarring
- Lack of response after 3-4 days of appropriate therapy
- Recurrent episodes
- History of HSV eye disease
- Immunocompromised state
- Neonatal conjunctivitis (requires systemic treatment)
Critical Clinical Pitfalls to Avoid
Never use topical corticosteroids in HSV conjunctivitis without antiviral coverage, as they potentiate viral replication and worsen infection. 1
Avoid indiscriminate antibiotic use - mild bacterial conjunctivitis is often self-limited and resolves spontaneously in 64% of cases by days 6-10 without treatment. 1 Consider delayed prescription strategy if patient is reliable for follow-up. 8
Reserve fluoroquinolones for appropriate cases to minimize resistance development - use for moderate-severe disease, contact lens wearers, or suspected resistant organisms. 9, 8
Monitor for treatment failure - advise patients to return if no improvement after 3-4 days, at which point cultures should be obtained and alternative diagnoses considered. 1, 9
Geographic resistance matters - in some regions, Pseudomonas aeruginosa resistance to moxifloxacin has increased from 19% to 52%, so awareness of local resistance patterns is crucial. 1