了解眼外肌在20MHz高频超声中的声像图特点，明确20MHz超声在眼外肌疾病中的适用范围及应用价值。 方法：自2011-01/12分别利用10MHz及20MHz高频超声对眼外肌进行对比观察，归纳总结正常人群眼外肌20MHz B型超声的声像图特点及其厚度，以及在不同眼外肌疾病中的表现。 结果：20MHz高频超声在正常人群及斜视患者中可以清晰地显示眼外肌的形态特点，正常人群双眼对称眼外肌厚度无明显差别。与10MHz超声相比，其测量值明显增大，两者差异有统计学意义。而在其他眼外肌疾病中表现各不相同。 结论：20MHz高频B型超声适合正常人群及斜视患者的眼外肌观察，其显示效果明显优于10MHz超声，而在眼外肌厚度增加类型的眼外肌疾病中的应用存在一定的限制。

To define the value of 20MHz high frequency B mode ultrasound in extraocular muscles disease. METHODS:10MHz and 20MHz B-mode ultrasound were used to observe the extraocular muscles on normal persons and different extraocular muscle diseases from Jan 2011 to Dec 2011. RESULTS:In the normal eyes and strabismus patients, 20MHz high frequency ultrasound could clearly show the morphological characteristics of the extraocular muscles. Symmetric extraocular muscle thickness was not significantly different in normal eyes. Compared with 10MHz ultrasound, its measured value was significantly increased. Different extraocular muscle diseases had different performance. CONCLUSION:20MHz high frequency ultrasound is suitable for observing extraocular muscles of the normal eyes and strabismus patients. The display is better than 10MHz ultrasound. But there are certain limitations in the types of extraocular muscle disease with extraocular muscle thickness increase.