A new concept of ocular infectious diseases includes two modes of pathogenesis, one being an acute inflammation caused by the attachment of free-floating bacteria, and another being intractable biofilm-related ocular infections. 15–20% of Staphylococcus epidermidis strains isolated from human conjunctiva exhibit slime formation and can be pathogens causing inflammation. Topical application, in the form of, for example, eye drops, of a combination of two antimicrobial agents is usually applied to treat such infections. Any antimicrobial agent having a post-antibiotic effect is generally administered in a twice-a-day regimen.