角膜前后表面高度不对称性图形分析

Analysis on the asymmetry of Orbscan-Ⅱ anterior and posterior topography

【目的】分析角膜地形图中角膜前、后表面立体高度不对称性图形的特点并探讨其临床意义。【方法】对拟行LASIK手术的近视患者进行Orbscan-Ⅱ角膜地形图测量,并观察其角膜前、后表面立体高度形态的表现。【结果】在27562例54669眼中,有291例432眼的近视患者的角膜前、后表面高度图表现出不对称的"CROSS"形式。432眼中16～25岁的171例215眼;中等近视-3.25～-6.00141例191眼;散光270例390眼;散光Ⅱ形193例300眼。【结论】拟行准分子激光屈光矫正手术者,术前均应对角膜的形态及屈光状态作精确测量,对存在"CROSS"shape者的手术更要慎重,合理设计手术方法及切削量,并对手术后效果作正确的评价。正确选择手术适应证是预防手术失败的关键,有利于提高手术成功率。

[ Objective] To analysis the asymmetry in Orbscan- Ⅱ anterior and posterior topography, and to discuss the clinical significance. [ Methods] To measure the topography in Orbscan- Ⅱ of the myopia patients who will be operated with LASIK, and to observe the differences of Orbscan-Ⅱ anterior and posterior topography. [Results] In 27 562 subjects, there were 291 cases （432 eyes） whose Orbscan- Ⅱ showed asymmetrical ＂cross＂ phenomenon.Among them 58.10 percent cases were between 16 and 25 ages, 44.21 percent cases diopter was between -3.25～ -6.00D and 90.28 percent was astigmatism. [ Conclusions] Exact measurement of corneal topography and refractive condition pre-operatively should be made who will be operated with LASIK, and it is very important to the ＂cross＂ phenomenon. The key of success or failure of operation are reasonable design the operation method and cutting amount correctly evaluate the effect of post-operation.