Treat if severe, as most viral or self-limiting.
Bacterial conjunctivitis is usually unilateral and also self-limiting; it is characterised by red eye with mucopurulent, not watery, discharge; 65% resolve on placebo by day five.
Fusidic acid has less Gram-negative activity.
If severe: chloramphenicol 0.5% drop and 1% ointment
2 hourly for 2 days then 4 hourly (whilst awake) at night
for 48 hours after resolution
Second line: fusidic acid 1% gel
Two times a day