Effect On The Retinal Function And Ultrastructure With Intravitreal Triamcinolone Acetonide

Purpose To investigate the effect of Triamcinolone Acetonide(TA) on the retinal function and ultrastructure of the rabbit eyes with different dose intravitreal injection. Methods 30 rabbits were randomly divided into one control group which received an intravitreal injection of 0.4ml saline solution and four treatment groups which received different intravitreal dose of the TA: 4mg(0.1ml), 8mg(0.2ml), 16mg(0.4ml), 32mg(0.8ml). Ophthalmoscopy and intraocular pressure were performed from 1 to 30 d after drug injection. We obtained electroretinography on d 30. Light ,electronmicroscopy(TEM) and TUNNEL studies were done on d 30. Results There had no statistical difference on intraocular pressure between control group and four treatment groups (p=0.325),so does the occurrence rate of cataract ,and b-wave amplitude among control group and 4mg and 8mg groups. The occurrence rate of cataract increase (H=16.682 P=0.001) and b-wave amplitude decrease (P<0.05)concurrently with 16mg and 32mg groups.Both light and TEM of the retina were nomarl among the normal control group and the 4mg group.There was obvious damage to the retina in the 16mg and 32mg group when examined by light,TEM and TUNNEL studies.The light microscopy was normal and the TEM can be seen little pathologic changes in the 8mg group. Conclusions As the dose of TA increased in the vitrous cavity,the effect of Triamcinolone Acetonide on the retinal function and ultrastructure is gradually obvious. The recommended safe clinical dose is 4mg,8mg is upper limit.