Repeat intravitreal injections are

Repeat intravitreal injections are likely to be of little benefit. Persisting levels of vitreousantibiotic in excess of MICs for 3 days or more after intravitreal injection have already beendiscussed, and repeating the same agents after 2-3 days will may not add to the treat-ment, but carries further risk of macular toxicity. Leung's group 81 looked at endophthalmitiscases with culture positive taps at time of second injection and noted universally poor out-comes, with most patients eventually undergoing vitrectomy at a later stage. The microbi-ology showed organisms with the same antibiotic sensitivities in the second tap as the firstin 94% of cases, indicating that this was not a matter of antibiotic resistance, but that therewas some other factor prolonging the clinic course of the infection. They postulated thatbacterial sequestering or biofilm production might have reduced the sensitivity of the mi-crobes to the antibiotics used. There was a non-significant trend that those receiving thesecond treatment later had worse final outcomes.