okay, I looked it up, and I'm not a vet, but it sounds to me like it should be discontinued.
Precautions
Most susceptible bacteria will respond to chloramphenicol therapy in a few days. If improvement is not noted in this period of time, a change of therapy should be considered.
When infection is suspected as the cause of a disease process, especially in purulent or catarrhal conjunctivitis, attempts should be made to determine through susceptibility testing, which antibiotics will be effective prior to applying ophthalmic preparations.
Vetrachloracin Ophthalmic Ointment Dosage And Administration
Application of the ointment should be preceded by cleansing to remove discharge and crusts. The ointment is applied every three hours around the clock for 48 hours, after which night instillations may be omitted. A small amount of ointment should be placed in the lower conjunctival sac. Treatment should be continued for two days after the eye appears normal. Therapy for cats should not exceed 7 days.