方法：将患者采用双盲法随机分为试验组、阳性对照组和空白对照组三组，每组50例100眼。试验组患者术后第1d开始使用拉坦前列腺素滴眼液1次，3mo后停用。阳性对照组早晚点噻吗洛尔眼液2次，3mo后停用。空白对照组不点任何降眼压类药物。观察术前、术后1wk； 1，3，6，12，24mo裸眼视力(UCVA)、主觉验光、角膜前表面曲率、角膜后表面曲率、眼压、BUT测定、Schirmer试验等方面的变化。

结果：试验组与阳性对照组未出现1例屈光回退病例，试验组48例能够坚持3mo内每天用一次拉坦前列腺素眼液，阳性对照组仅有41例能坚持3mo内每天用2次噻吗洛尔眼液，有统计学差异。空白对照组出现4例屈光回退病例，与试验组有统计学差异，三组患者BUT、Schirmer试验无明显差异。

结论：拉坦前列腺素眼液可有效预防准分子激光原位角膜磨镶术后屈光回退，副作用小，患者依从性更好。

METHODS:Patients were randomly divided into experimental group, positive control group and blank control group, each group of 50 cases(100 eyes). In experimental group, patients used latanoprost eye drops once from the first day after the operation, and the eye drops were discontinued after three months. The positive control group applied timolol eye drops in the morning and evening respectively, and the eye drops were discontinued after three months. Blank control group without any ocular hypotensive drugs. Effect of preoperative, postoperative 1 week,1 month,3,6,12,24 months, the uncorrected visual acuity(UCVA),subjective refraction, corneal posterior surface, intraocular pressure, BUT, Schirmer test and other aspects of the change were observed.

RESULTS:There was no retreatment cases in experimental group and positive control group. Forty-eight cases of experimental group were able to adhere to employ latanoprost ophthalmic solution once daily for three months, while the positive control group had only 41 cases adhering to use timolol eye drops twice daily for three months. There was significant difference. The blank control group of 4 retreatment cases were appeared, there were significant differences compared with experimental group. No significant differences in BUT, Schirmer test among three groups were found.

CONCLUSION:Latanoprost eye drops can effectively prevent excimer laser in situ keratomileusis retreatment, with less side effects and better patient compliance.