Effects of vancomycin and ofloxacin on rabbit ERG in vivo

The retinal toxicity of vancomycin and ofloxacin was studied by electroretinogram (ERG) recorded before and after intravitreal injection in rabbits. A dose of 1.0 mg vancomycin caused no change in the ERG for at least 8 weeks after the injection. The ERG was nonrecordable during one to four weeks after an intravitreal injection of 10 mg vancomycin, with recovery of only the c-wave. A dose of 200 micrograms ofloxacin did not cause deterioration of the b-wave, the c-wave or the oscillatory potentials throughout the follow-up period of 8 weeks. Considering the individual susceptibility of the ERG components to these antimicrobial agents and taking into account the difference in vitreous volume between the rabbit and man, the results of this study indicate the recommended intravitreal doses of these antimicrobial agents for clinical use are as follows: vancomycin 1.0 mg/0.1 ml, and ofloxacin 200 micrograms/0.1 ml.