Objective To observe the effects and possible mechanism of Ziyin Mingmu Pills（滋阴明目丸） on retinal pigment epithelial（RPE） cells after light injury. Methods A total of 60 SD rats were divided into Ziyin Mingmu Pills low

medium and high dose groups and a blank group

with 15 rats in each group. The groups of different Ziyin Mingmu Pills dosages were respectively administered with the suspension of Ziyin Mingmu Pills at a concentration of 0. 39

0. 78

and 1. 56 g/ml. The gavage volume was 34 ml/（kg · d）

and the blank group was given34 ml/（kg·d） of normal saline for gavage

each group was administered for 7 days. The drug-containing serum was prepared in the end of the gavage

and the concentration of the drug-containing serum in the subsequent experiment was screened by the MTT method. The selected cells for experiment were divided into a blank group（without drugcontaining serum）

serum group（with drug-containing serum）

model group（light damage modeling

no drug-containing serum）

and Chinese medicine group（light damage modeling with drug-containing serum）. After 24 hours of culture

the in vitro RPE cell light damage models of model group and the Chinese medicine group were established.The apoptosis rate of each group was measured

and the expression of caspase-1

caspase-3 and mRNA were measured. Results The medium dose serum was the optimal dose

and it was used in subsequent experiments. Compared with the blank group

the apoptosis rate

expression of Caspase-1 and Caspase-3 protein and mRNA in serum group were not statistically significant（P > 0. 05）. The apoptosis rate

Caspase-1 and Caspase-3 protein and mRNA expression in the model group increased significantly（P < 0. 05）. Compared with the model group

the apoptosis rate

Caspase-1 and Caspase-3 protein and mRNA expression in the Chinese medicine group were significantly decreased（P < 0. 05）. Conclusion Ziyin Mingmu Pills can effectively inhibit the apoptosis of RPE cells after light injury. The mechanism may be related to the inhibition of the expression of Caspase-1

Caspase-3 protein and its mRNA.