Morlet N, Lindsay P A
Department of Ophthalmology, University of New South Wales, Australia.
J Cataract Refract Surg. 1995 Nov;21(6):616-9. doi: 10.1016/s0886-3350(13)80555-x.
Intraoperative keratometry enables the surgeon to set an appropriate amount of corneal astigmatism with the suture tension. Errors in estimating or measuring the astigmatism can occur with hand-held keratometers because the distance an object is held from an astigmatic cornea influences the shape of the elliptical image. Thus hand-held instruments should be held at a calibrated distance. We have designed a new hand-held keratometer, the keratoscopic astigmatic ruler, to assess the magnitude of corneal astigmatism. It consists of a rack of elliptical keratoscopic lenses corresponding to increasing magnitudes of astigmatism and is made from inexpensive autoclavable injection-molded plastic. The ruler's keratoscopic lenses refract light, creating a real aerial image above the cornea that produces a bright and easily determined corneal reflection. The ruler incorporates a sight to allow the user to hold the ruler at the correct distance.
术中角膜曲率测量可使外科医生通过缝线张力来设定适当的角膜散光量。使用手持角膜曲率计估计或测量散光时可能会出现误差，因为手持物体与散光角膜的距离会影响椭圆形图像的形状。因此，手持仪器应保持在校准距离。我们设计了一种新型手持角膜曲率计——角膜散光测量尺，用于评估角膜散光的程度。它由一系列对应于散光程度增加的椭圆形角膜镜透镜组成，由廉价的可高压灭菌的注塑塑料制成。该测量尺的角膜镜透镜使光线发生折射，在角膜上方形成一个真实的空中图像，产生明亮且易于确定的角膜反射。该测量尺设有瞄准器，以便使用者将测量尺保持在正确的距离。
