AIM: To research the curative effect of dexamethasone on rat cornea acid burn at different periods.

METHODS: The 40 corneal acid burned eyes of the 40 SD rats were divided into 4 groups with each group of 10 eyes randomly. Ⅰ, Ⅱ, Ⅲ groups were treated with dexamethasone(1mg/mL)eye drops at three periods after the corneal burns(acute stage, 0-3d; early repair, 3-7d; late repair, 7-21d); the Ⅳ group is treated without dexamethasone. The injured eyes were photographed and dynamically observed with slit lamp microscope, and the histological changes were scrutinized with HE staining.

RESULTS: Eventually, the cornea repairing situation from good to bad is: Ⅲ, Ⅰ, Ⅳ, Ⅱ. After acid burned, corneal epithelial healing and angiogenesis area were different, the comparison between the experimental groups and control group was statistically significant(P<0.01).

CONCLUSION: After acid burned, curative effects are different with using dexamethasone at different periods. Active effects were produced after using dexamethasone in the acute stage and the late stage. However, using dexamethasone in the early stage may hinder the repairing of cornea, or even dissolve the cornea.