方法：新鲜的猫眼球20只，随机平均分为4组(A、B、C、D组)，分别在不同的模式下进行飞秒激光角膜基质板层切割：A组为常规切割组：负压吸引环吸引、角膜完全压平，压平直径约为13mm； B组不使用负压吸引环、角膜完全压平，压平直径约13mm； C组负压吸引环吸引、角膜压平直径约为8mm； D组不使用负压吸引环、角膜压平直径约为8mm。采用5分制的评分标准，对切割后的猫角膜基质界面的电子显微镜扫描照片进行评分，以评估切割后的角膜基质界面的光滑度。

结果：裂隙灯显微镜图片显示出四组角膜基质界面光滑度的结果，D组最光滑，A组最粗糙。30倍扫描电镜照片的评分结果显示D组光滑度明显优于A组(P=0.007)，D组光滑度明显优于B组(P =0.007)， D组光滑度明显优于C组(P =0.016)。100倍电镜照片评分结果显示D组光滑度明显优于A组(P =0.01)，D组光滑度明显优于B组(P =0.016)。其余各组间差异无统计学意义。

结论：在无负压环吸引且压平面积小的模式-对角膜组织的压缩变形较小的切割状态下，飞秒激光辅助的猫角膜基质后板层切割界面的光滑度可得以部分改善。

METHODS: A total of 20 fresh cat eyeballs were randomly separated into 4 groups: Group A, the routine(control)group, cuts were made using a suction ring and complete corneal applanation within an approximate diameter of 13 mm; Group B, no suction ring was used, but complete corneal applanation was performed using an approximate diameter of 13 mm; Group C, a suction ring was used, and corneal applanation was performed using an approximate diameter of 8 mm; and Group D, no suction ring was used, and corneal applanation was performed using an approximate diameter of 8 mm. Scanning electron microscopy(SEM)images of the resulting PCSI were graded for ridges and roughness using a subjective 5-point grading scale.

RESULTS: Photography performed using a slit lamp microscope showed that the best PCSI was achieved in Group D, and the worst group was Group A. SEM images(×30 magnification)indicated that the macroscopic interface quality was significantly different between Group D and Group A(P=0.007), between Group D and Group B(P=0.007), and between Group D and Group C(P=0.016). Other SEM images obtained at ×100 magnification indicated that the grades for the microscopic surface quality between Group D and Group A(P=0.01)and between Group D and Group B(P=0.016)were significantly different. The grades of the other groups were not significantly different.

CONCLUSION: The quality of PCSI on the cat corneas can be partially improved if the deformation of the extruded corneal stroma is slight without using suction ring or an excessive corneal applanation scope by the applanation cone.