BACKGROUND AND OBJECTIVE: To assess the retinal toxicity of varying concentrations of intravitreally injected gatifloxacin and levofloxacin. MATERIALS AND METHODS: In this experimental, controlled study, levofloxacin (initial concentration = 25 mg/mL) and gatifloxacin (initial concentration = 2 mg/mL) were titrated using 5% dextrose solution to concentrations of 2,500 to 156 microg/0.1 mL and 400 to 50 microg/0.1 mL, respectively. Each concentration was injected intravitreally into two rabbit eyes (one eye per animal); two control eyes were injected with 0.1 mL of 5% dextrose solution. All animals were examined and electroretinography was performed before and 14 days after injection. The animals were killed at 14 days; the eyes were enucleated and prepared for light microscopy. RESULTS: The levofloxacin group exhibited significant decreases in electroretinography in the eyes injected with 1,250 and 2,500 microg. No signs of retinal toxicity were observed on slit-lamp examination, indirect ophthalmoscopy, or light microscopy in all eyes injected intravitreally with 625 microg or less of levofloxacin or in any eyes given gatifloxacin. CONCLUSION: Intravitreally injected concentrations of 625 microg or less of levofloxacin and 400 microg or less of gatifloxacin appeared nontoxic.
BACKGROUND AND OBJECTIVE: To assess the retinal toxicity of varying concentrations of intravitreally injected gatifloxacin and levofloxacin. MATERIALS AND METHODS: In this experimental, controlled study, levofloxacin (initial concentration = 25 mg/mL) and gatifloxacin (initial concentration = 2 mg/mL) were titrated using 5% dextrose solution to concentrations of 2,500 to 156 microg/0.1 mL and 400 to 50 microg/0.1 mL, respectively. Each concentration was injected intravitreally into two rabbit eyes (one eye per animal); two control eyes were injected with 0.1 mL of 5% dextrose solution. All animals were examined and electroretinography was performed before and 14 days after injection. The animals were killed at 14 days; the eyes were enucleated and prepared for light microscopy. RESULTS: The levofloxacin group exhibited significant decreases in electroretinography in the eyes injected with 1,250 and 2,500 microg. No signs of retinal toxicity were observed on slit-lamp examination, indirect ophthalmoscopy, or light microscopy in all eyes injected intravitreally with 625 microg or less of levofloxacin or in any eyes given gatifloxacin. CONCLUSION: Intravitreally injected concentrations of 625 microg or less of levofloxacin and 400 microg or less of gatifloxacin appeared nontoxic.