What are the best eye drops to use for a patient presenting with conjunctivitis (pink eye)?

Best Eye Drops for Pink Eye (Conjunctivitis)

For viral conjunctivitis (the most common type), supportive care with artificial tears and topical antihistamines is recommended, as antibiotics provide no benefit; for bacterial conjunctivitis, topical antibiotics modestly speed resolution but most cases self-resolve; for allergic conjunctivitis, topical antihistamines with mast cell-stabilizing activity are first-line treatment. 1, 2

Determining the Type of Conjunctivitis

The treatment depends entirely on identifying whether the conjunctivitis is viral, bacterial, or allergic:

Viral Conjunctivitis (Most Common in Adults)

• Watery discharge is the hallmark finding 1
• Often follows upper respiratory infection or exposure to someone with "pink eye" 2
• Typically bilateral involvement with preauricular lymphadenopathy 3
• No treatment with antibiotics is needed as this is a self-limiting condition 1, 2

Bacterial Conjunctivitis (More Common in Children)

• Mucopurulent discharge with eyelids matted shut upon waking is the key distinguishing feature 1
• Lack of itching and no history of prior conjunctivitis episodes favor bacterial etiology 2
• Unilateral presentation is more common initially 3

Allergic Conjunctivitis

• Itching is the most consistent and distinguishing symptom 2, 4
• Watery discharge with bilateral involvement 1
• History of atopy or seasonal pattern 4

Treatment Recommendations by Type

For Viral Conjunctivitis (No Antibiotics Needed)

• Artificial tears (preferably refrigerated) for symptomatic relief 1, 4
• Topical antihistamine eye drops (e.g., ketotifen) for comfort, 1 drop twice daily 5, 1
• Cold compresses for additional symptom relief 1, 4
• Strict hand hygiene to prevent transmission 1
• Avoid antibiotics as they provide no benefit and may cause adverse effects 6

For Bacterial Conjunctivitis

Topical antibiotics modestly speed resolution but are not always necessary, as 41% of cases resolve spontaneously by days 6-10 without treatment 7. However, antibiotics allow earlier return to work/school and provide modest benefit 2, 7.

Recommended antibiotic options (all have similar efficacy):

• Trimethoprim-polymyxin B ophthalmic solution 8
• Gentamicin sulfate ophthalmic solution 8
• Sodium sulfacetamide ophthalmic solution 8
• Moxifloxacin drops (broad-spectrum fluoroquinolone) 4

Clinical response typically occurs within 3-6 days, with 84-89% cure rates by 2-7 days after completing therapy 8. Delayed antibiotic prescribing (waiting 2-3 days) has similar outcomes to immediate prescribing 1.

For Allergic Conjunctivitis

First-line treatment:

• Topical antihistamines with mast cell-stabilizing activity are the treatment of choice 4, 2
• Over-the-counter options include ketotifen (1 drop twice daily, every 8-12 hours) 5
• Refrigerated artificial tears to dilute allergens and provide cooling relief 4
• Cold compresses 4

For persistent or severe allergic conjunctivitis:

• Brief course (1-2 weeks) of topical corticosteroids with low side-effect profile (loteprednol etabonate or fluorometholone) if symptoms are not adequately controlled 4
• Topical cyclosporine 0.05% or tacrolimus for severe cases requiring steroid-sparing therapy 4

Avoid oral antihistamines as they may worsen dry eye and actually exacerbate allergic conjunctivitis 4

Critical Red Flags Requiring Ophthalmology Referral

Immediate referral is indicated for: 1

• Severe pain or photophobia
• Decreased vision
• Conjunctivitis in a neonate
• Recent ocular surgery
• Vesicular rash on eyelids or nose (suggesting herpes)
• History of rheumatologic disease
• Immunocompromised state
• Contact lens wearer with suspected bacterial conjunctivitis (risk of serious corneal infection)

Important Caveats

• Do not confuse viral subepithelial infiltrates (occurring 1+ weeks after adenoviral conjunctivitis) with HSV keratitis, as corticosteroids are contraindicated in active HSV epithelial disease 9, 6
• Avoid punctal plugs in allergic conjunctivitis as they prevent flushing of allergens and inflammatory mediators 4
• If using topical corticosteroids for any reason, monitor intraocular pressure and evaluate for cataract formation with regular follow-up 4, 9
• Most uncomplicated bacterial conjunctivitis resolves in 1-2 weeks without treatment 2
• Gonorrhea or chlamydia conjunctivitis requires systemic antibiotics in addition to topical therapy 2