The conjunctiva is the outermost covering of the eyeball, and also lines the eyelids (see Diagram — Anatomy of the Eye). Bacteria here are much less common than viruses, but do cause the infection sometimes. Bacterial disease in general is usually more severe than viral (see Differences Among Germs), and runs a rare risk of eye damage in the long run.
Bacterial Conjunctivitis usually just involves one eye, which is red. It may itch or feel gritty, but does not hurt (true pain suggests more serious illnesses). The vision is normal (except it may feel blurry now & then due to tears, but certainly not blurry all the time).
We distinguish bacterial from viral disease because with bacteria, there’s constant discharge all through the day in the corner of the eye. It may be white, yellow, or green — wipe it away, & more accumulates very quickly. There are very rare cases of Gonorrhea Conjunctivitis, where the eye is rapidly & completely covered with pus; such patients need referral to an ER for IV treatment.
Antibiotic eye drops work for typical Bacterial Conjunctivitis (but not for viral conjunctivitis). A week or so of therapy will cure the infection. The patient still needs to practice careful hygiene & wash their hands, as much as possible.
Don’t use over-the-counter drops. Some (like ketotifen) can help with itching, but ask a pharmacist for help, & say you don’t want a “vasoconstrictor.” Those get rid of redness, but do so by cutting off circulation, which isn’t healthy at all (especially not if there’s a bacterial infection). And don’t buy artificial tears, which are no more useful than tap water.