Besifloxacin ophthalmic is used to treat bacterial conjunctivitis (pinkeye; infection of the membrane that covers the outside of the eyeballs and the inside of the eyelids). Besifloxacin is in a class of medications called fluoroquinolones. It works by killing the bacteria that cause infection. Besifloxacin comes as an ophthalmic suspension (eye drops) to apply to the eyes. It is usually applied to the affected eye(s) three times a day, 4 to 12 hours apart, for 7 days. Use besifloxacin eye drops at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use besifloxacin eye drops exactly as directed. Do not use more or less of it or use it more often than prescribed by your doctor.