摘要
目的 :探讨Orbscan Ⅱ眼前节分析仪在准分子激光原位角膜磨镶术术前检查中的应用价值并确定各项参考指标。方法 :在准分子激光原位角膜磨镶术术前利用Orbscan Ⅱ检查 ,取其中的前、后表面高度图、厚度图进行分析。比较其厚度测量与超声测厚的差别 ,确定前、后表面高度图的分类 ,角膜前、后表面形态及正常值。结果 :对 16 4只眼进行超声测量 ,所得的瞳孔中央平均厚度为 (5 46 .4± 30 .5 ) μm ,Orbscan Ⅱ测量的瞳孔角膜中央厚度为 (5 17.0± 33.0 ) μm ,角膜最薄点厚度为 (5 12 .9± 33.8) μm ,有 46 .95 %位于角膜颞下方。超声测厚与Orbscan Ⅱ瞳孔中央厚度相比平均厚约 (2 9.3± 13.1) μm ,与最薄点相比平均厚约 (33.5± 13.8) μm(P <0 .0 5 )。前、后表面高度图按形状都可分为中央岛、不完全桥、规则桥、不规则桥、群岛型和未分类型。角膜后表面理想球面的平均屈光力为 (5 1.8± 2 .0 )D ,后表面最顶点距理想球面的距离为 (31.0± 8.0 ) μm。 结论 :Orb scan Ⅱ对于准分子激光原位角膜磨镶术术前检查具有重要临床意义 ,但对于角膜测厚的功能准确性较差 。
Objective:To study the usefulness and indices of an Orbscan Ⅱ exam before laser in situ keratomileusis(LASIK).Methods:Before LASIK, the anterior and posterior elevation maps and pachymetry maps were scanned and the classification and normal indices of the figures were analyzed. At the same time, pachymetry was also measured by ultrasound A and compared to that of the Orbscan Ⅱ.Results:164 eyes were measured. The mean pachymetry of the cornea on the center of the pupil measured by ultrasound A was (546.4±30.5)μm. The same point measured with Orbscan Ⅱ was (517.0±33.0)μm and the thinnest point on the cornea was (512.9±33.8)μm. Compared to the ultrasound A index, corneal thickness at the pupil center was (29.3±13.1)μm thinner and the thinnest point of the cornea was (33.5±13.8)μm less (P<0.05). Based on the shape, the anterior and posterior elevation maps can also be classified as: central island, incomplete ridge, regular ridge, irregular ridge, archipelago and unclassified pattern. The mean keratometry of the posterior best fit surface (BFS) was (51.8±2.0)D and the distance from the apex to the BFS was (31.0±8.0)μm.Conclusion:Orbscan Ⅱ has important clinical significance before LASIK. However, it is not quite accurate in measuring pachymetry, so ultrasound A cannot be completely replaced.
出处
《眼视光学杂志》
2001年第3期133-136,共4页
Chinese Journal of Optometry & Ophthalmology
