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眼镜镜片屈光度的测量一般都用镜片测度表或镜片测度仪。但一般医院眼科多没有上述两项器械,现介绍透镜的一种简易测量方法:1.判定镜片是球面透镜抑或柱镜以5m 远的一十字线为目标。(如视力表一直角两边)把未知透镜置于眼前33cm 处旋转,观察两直角边有无出现剪动。若无说明该透镜是球面透镜;若有剪动,则含有柱镜成分。2.定心——光学中心的确定对球面透镜,缓慢上下左右移动,使两直角边透过透镜成的像和两直角边相重叠时,此时直角顶点即是透镜的光学中心;对球柱镜,先旋转透镜使通过透镜见到一直角,然后缓慢上下左右移动透镜,使物像所在的直线重叠,记下垂直线的位置,这就是主子午线,与此垂直的线即第二子午线。两线相交处即光心。3.利用透镜的视觉像移判定透镜的正负
Spectacles lens refraction measurements are generally used lens or lens measuring instrument. However, the general hospital ophthalmology more than the above two devices, are introduced a simple measurement method of the lens: 1. To determine whether the lens is a spherical lens or cylinder to 5m away a cross line as the goal. (Such as the eye chart on both sides of the right angle) to the unknown lens placed in front of 33cm Department of rotation, observe the existence of two right-angle edge shearing. If not explained that the lens is a spherical lens; if there is shear, it contains the cylinder components. 2. centering - the optical center to determine the spherical lens, slowly move up and down, so that the two right-angle edge through the lens into the image and the two right-angle edge of the overlap, then the right-angle vertex is the optical center of the lens; the ball Lenticular, first rotate the lens so that the lens to see a right angle, and then slowly move the lens up and down, so that the image where the line overlap, write down the position of the vertical line, which is the main meridian, and the vertical line that the second meridian. The intersection of two lines is the optical center. 3. The use of lens vision to determine the positive and negative lens shift