A school outbreak of red watery eyes — viral conjunctivitis; hygiene, not antibiotics. Viral (adenovirus — watery discharge, highly contagious, preauricular nodes): supportive — cold compress, hygiene; antibiotics don't help. Bacterial (purulent — antibiotic drops; ophthalmia neonatorum — gonococcal/chlamydial in newborns — emergency: ceftriaxone + erythromycin prophylaxis at birth). Allergic (itching dominant — antihistamines, avoid rubbing). Trachoma (Chlamydia trachomatis — repeated infection → entropion → corneal blindness; SAFE: Surgery, Antibiotics — azithromycin, Facial cleanliness, Environmental). The itchy eye is allergy — the watery contagious one is viral.