Safety of Intravitreal Ciprofloxacin in Phakic Rabbit Eyes Determined with Electroretinography

ABSTRACT

This study was conducted to determine the safe intravitreal dosage of ciprofloxacin. Twenty-four phakic eyes of New Zealand pigmented rabbits were used. Each group(4 eyes) received midvitreal ciprofloxacin of 100, 200, 400, 600, 800 micro gram in 0.1ml BSS Plus, or 0.1ml BSS Plus only as control. We evaluated retinal function by measuring the electroretinograms for a graded series of flash intensities and fitting b-wave amplitudes to the Naka-Rushton equation. At a dose of greater than 600 micro gram, Rmax decreased signifantly and log K increased signifantly. N-value decreased slightly. B-wave amplitude decreased as a toxic response of intravitreal ciprofloxacin in a dose dependent manner, and this response was best detected using lower luminance stimuli. Lower luminance electroretinography revealed a significant decrease in b-wave amplitude in eyes injected with a dose of 400 micro gram or more. We concluded that 200 micro gram will be the safe intravitreal dosage of ciprofloxacin in phakic rabbit eyes.