since antibiotic eye drops are used from 5-10 days and not all pink eye (conjunctivitis) is bacterial (viral and allergic conjunctivitis does not respond to antibiotic drops) i usually tell my patients to use the drops at least 24 hours and see an improvement before returning to school (assuming this is a child). the drops should be administered at school on the same schedule. adults are less likely to spread this infection simply because they practice a higher level of personal hygiene so returning to work is usually not restricted unless the infection is extensive.
after start of treatment how long is pink eye contagious