In order to explore retinal toxicity and to estimatequot;safe dosagequot;of intravitreal gentamicin 21 Dutch-belted rabbits divided into 5 dosage groups and 1 control group were investigated.The results showed that, in 3 000mu;g group, optic disc swelling and vein dilating were observed ophthalmoscopieally. Histopathologie study displayed the retinal necrolysis. In 50~500mu;g groups,the retinal pigment change was revealed within 3~14 days after the injection.Histopathologic study displayed that the retinal damages were confined in outer layers of retina in early stage. Inner layers of retina were also influenced in late stage. The results demontrated that with increasing intravitreal gentamiein,retinal damages are gradully aggravated,and even if intravitreal gentamicin was in minimum dose,retinal damages was still observed. （Chin J Ocul Fundus Dis,1994,10:167-169）
In order to explore the histochemical changes in retina after intravitreal injection of gentamycin,a histochemical quantitative analysis of cytochrome oxidase(CYO)and acetylcholinesterase(ACHE)was performed with a computerized image analysis system and was compared with that of morphological study.The results showed that CYO decreased significantly in 100mu;g dosage group.With increasing intravitreal gentamycin dosage or observed days,CYO decreased gradually in all rabbits.In 100~500mu;g dosage groups,ACHE changed mildly at 3 days of injection.It decreased significantly at 7 days.However,it was destroyed completely in 1000~3000mu;g dosage groups at 3 days. （Chin J Ocul Fundus Dis,1994,10:232-235）