方法：40只SD大鼠的40只角膜酸烧伤眼按随机数字法分成4组，每组10只，其中Ⅰ，Ⅱ，Ⅲ组为治疗组，分别于角膜烧伤后0～3，3～7，7～21d使用地塞米松滴眼； Ⅳ组为空白对照组。于烧伤后使用裂隙灯显微镜动态观察角膜上皮缺损直径、角膜新生血管及角膜基质混浊程度并照相，并取角膜行HE染色观察角膜各层组织的形态学变化。

结果：最终角膜修复优良情况依次为Ⅲ组，Ⅰ组，Ⅳ组，Ⅱ组； 酸烧伤后各组角膜上皮愈合速度和新生血管面积不同，不同时期的实验组与对照组间的比较有统计学意义(P<0.01)。

结论：在酸烧伤后不同时期使用地塞米松，疗效存在差异。在急性期和修复晚期使用地塞米松能够促进角膜的修复，在修复早期使用地塞米松则会阻碍角膜的修复甚至可促使角膜溶解。

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.