[Morphological changes in the retina following one-shot injection of netilmicin sulfate into the vitreous].

Morphological changes of the retina following one-shot injections into the vitreous of netilmicin sulfate were investigated. The concentrations of netilmicin in the vitreous after intravitreal injection showed the curve of y = a/xb, where y is the concentrations in the vitreous body, x in the number of days since injection and a, b are constant. Concentration decreased rapidly after the injection, and almost totally disappeared after one week. Morphologically, the retina showed normal structure following injections of 100 micrograms/0.1ml and 200 micrograms/0.1ml. Following injections of over 500 micrograms/0.1ml, the outer segment of the photoreceptor disappeared and many phagosomes appeared in the retinal pigment epithelium cell. Following one shot injections of over 500 micrograms/0.1ml damage to the photoreceptor and retinal pigment epithelium was demonstrated. The above data suggested that one-shot injection of netilmicin in concentrations of up to 200 micrograms/0.1ml could be mode without retinal damage.