Au Y K, Reynolds M D, Chadalavada R C
Department of Ophthalmology, Louisiana State University, Shreveport.
Refract Corneal Surg. 1991 Jul-Aug;7(4):299-302.
Reproducible results in refractive keratectomy are greatly influenced by an accurate setting of the diamond knife blade length. In this study, we evaluated the accuracy and reproducibility of three existing techniques of blade calibration: the KOI coin gauge, the KOI diamond knife handle micrometer, and the Magnum optical micrometer. Serial blade length measurements of three similarly designed KOI diamond knives were made using each of the above calibration methods. The three knife handle micrometers had the largest measurement error (3.55%, 2.83%, 1.82%), and therefore the sole reliance of the handle micrometer for blade calibration was not recommended. The measurements made by the coin gauge on the three knives had measurement errors of 1.03%, 1.64%, and 1.46%. The optical micrometer achieved an accuracy of 0.005 mm and an interobserver precision of 0.009 mm. We prefer using the optical micrometer because the potential for parallax error is eliminated; it has a lower risk of blade damage; it is easier to use; and it also allows detection of defects in the footplates, the diamond knife, and of the wobbling blade, which may contribute to calibration error.
准分子激光原位角膜磨镶术（PRK）中可重复的结果很大程度上受到钻石刀刀片长度精确设置的影响。在本研究中，我们评估了三种现有刀片校准技术的准确性和可重复性：KOI硬币量规、KOI钻石刀柄千分尺和Magnum光学千分尺。使用上述每种校准方法对三把设计相似的KOI钻石刀进行连续刀片长度测量。三种刀柄千分尺的测量误差最大（3.55%、2.83%、1.82%），因此不建议仅依靠刀柄千分尺进行刀片校准。硬币量规对三把刀的测量误差分别为1.03%、1.64%和1.46%。光学千分尺的精度达到0.005mm，观察者间精度为0.009mm。我们更喜欢使用光学千分尺，因为它消除了视差误差的可能性；刀片损坏的风险较低；使用更方便；并且它还可以检测刀头、钻石刀和摆动刀片中的缺陷，这些缺陷可能会导致校准误差。
