Smith G, Atchison D A
Am J Optom Physiol Opt. 1983 Mar;60(3):216-23. doi: 10.1097/00006324-198303000-00009.
Rotationally symmetrical aspheric surfaces of spectacle lenses are constructed as either "zonal aspherics" or "continuous aspherics." Zonal aspherics consist of annular zones surrounding a central zone with each zone being nominally spherical with progressively lower surface power the farther the zone is from the surface vertex. Aspheric surfaces are often specified by the radial drop in surface power from the center to the edge of the lens (e.g., Welsh Four-drop), but for assessment purposes the surface shape must be specified more precisely. The formulas for the description of continuous aspherics can be manipulated into different forms. Mathematical descriptions are given or developed which will enable theoretical assessment of the performances of all lenses with rotationally symmetrical aspheric surfaces.
眼镜镜片的旋转对称非球面表面被构造为“分区非球面”或“连续非球面”。分区非球面由围绕中心区域的环形区域组成，每个区域名义上是球面，离表面顶点越远，表面屈光力逐渐降低。非球面表面通常由镜片中心到边缘的表面屈光力的径向下降来指定（例如，威尔士四降），但为了评估目的，表面形状必须更精确地指定。用于描述连续非球面的公式可以被变换成不同的形式。给出或推导了数学描述，这将能够对所有具有旋转对称非球面表面的镜片的性能进行理论评估。
