Campbell C
Humphrey Instruments, San Leandro, California, USA.
Optom Vis Sci. 1998 Mar;75(3):197-207. doi: 10.1097/00006324-199803000-00025.
Corneal irregularities can create conditions in which monocular diplopia, "ghost images," and multiple images of various types occur, thus degrading vision. For these secondary images to occur, corneal irregularities must create areas which form: (1) images which are displaced from the primary image; (2) sufficiently focused images; and (3) images which have sufficient contrast to be noticed in the presence of the primary image. Criteria necessary to satisfy these three conditions using measurable data are developed. The concept of a differential deflection field is introduced, and a method to create this field using corneal topography data is developed. It is shown how to use differential deflection field data to assess if conditions necessary for creating secondary images will occur in cases of corneal distortion.
角膜不规则性会导致出现单眼复视、“重影”以及各种类型的多个图像等情况，从而降低视力。要出现这些次生图像，角膜不规则性必须形成以下区域：（1）与原始图像有位移的图像；（2）聚焦充分的图像；（3）在原始图像存在时对比度足够高从而能被注意到的图像。利用可测量数据满足这三个条件所需的标准得以制定。引入了微分偏折场的概念，并开发了一种利用角膜地形图数据创建该场的方法。展示了如何使用微分偏折场数据来评估在角膜变形情况下是否会出现产生次生图像所需的条件。
