小梁切除术对角膜地形图的影响

目的：探讨小梁切除术对角膜屈光状态的影响及程度。方法：对30例(40只眼)原发性青光眼手术前后进行角膜地形图检查并对比分析，根据术前散光状态分为循规性散光组和逆规性散光组。结果：手术后1～2周角膜地形图变化与手术前相比循规性散光组散光增加，经统计学处理差异有显著性，逆规性散光组术后散光较术前减少，差异有显著性。角膜不规则参数(cornea irregular measurement，CIM)及形状参数(shape foctor，SF)也有小波动。手术后3个月角膜地形图变化与手术前相比差异无显著性。结论：小梁切除术后早期可产生一定程度的手术源性循规性散光，3个月后角膜屈光状态基本回复到术前状态，术后早期散光的产生与眼压的变化、手术切口及缝线有关。

Study of the effect of trabeculectomy on corneal topography

Objective:To evaluate the effect and its extent of ablation of trabecula on the refraction of cornea.Method:A contrast analysis of the corneal topography was made pre- and post-operatively on 30 patients (40 eyes) with primary glaucoma which were divided into two groups of direct and inverse astigmatism according to the state of astigmatism.Results:The contrast between the changes in the corneal topography one to two weeks after operation and before the operation shows that astigmatism progressed in the direct astigmatism group while diminished in the inverse astigmatism group.Both instances showed statistic significance.Cornea irregular measurement (CIM) and shape factor (SF) in early stage also showed some fluctuation.But the changes in the corneal topography three months post operatively did not show significant difference in contrast with that preoperatively.Conclusion:The ablation of trabecula in patients with glaucoma will cause a certain degree of direct astigmatism by the operation in early stage,but 3 months later the refraction of cornea will return to its pre-operative state.The degree of astigmatism in early stage after the operation is related to the changes of ocular pressure,the size of incision and the suture.