由外界物体发出的所有光线,经眼的屈光系统屈折后在视网膜上,应形成一个与物体大小不等,而形状完全相同的像,但实际上并非完全相同,这称为像差。像差会影响像的质。像差包括球面像差、色像差、像散、慧差畸变等。在像差中,像散和慧差等轴外像差居次要地位,而球面像差最为重要,也是影响视网膜像的重要因素,其根据如下:第一点是对光轴外物点产生的轴外像差,视网膜本身周边区的分辨力比中心区低的多。这是由于视网膜的结构和功能所决定的。第二点是通过瞳孔中心的光与通过瞳孔周边的光相比,若光能量相同,后者要暗的多。第三点是由于眼球的运动,欲看物体的像通常自 All light emitted by objects from the outside world, after refractive refractive system in the eye on the retina, should be formed with an object of the same size, but the shape of the same image, but in fact not exactly the same, which is called aberration. Aberration affects the quality of the image. Aberrations include spherical aberration, chromatic aberration, astigmatism, coma aberration and the like. In aberrations, astigmatism and coma and other axial aberrations in the secondary status, and spherical aberration is the most important, but also affect the retinal image of an important factor, which is based on the following: The first point is the optical axis of the physical point of occurrence Of the axial aberration, the resolution of the peripheral area of ​​the retina itself is much lower than the central area. This is due to the structure and function of the retina. The second point is that light passing through the center of the pupil is darker than light passing through the pupil, if the light energy is the same. The third point is due to eye movement, want to see the image of the object usually from