Harris W F
Department of Optometry, Rand Afrikaans University, Auckland Park, South Africa.
Ophthalmic Physiol Opt. 1994 Apr;14(2):203-9. doi: 10.1111/j.1475-1313.1994.tb00110.x.
A matrix expression is derived for the prismatic effect in the reading portion of a bifocal lens. Using this expression the problem of finding the location of the optical centre of the reading portion is examined. Matrix methods lead to a complete solution that holds in all circumstances within the usual limitations of first-order optics and thin lenses. Both the main and segment lenses may be astigmatic. In the usual case there is a unique near optical centre but situations can occur in which there is no near optical centre or an infinite number of them. These situations are examined systematically. Numerical examples illustrate the method.
推导了双焦点透镜阅读部分棱镜效应的矩阵表达式。利用该表达式研究了确定阅读部分光学中心位置的问题。矩阵方法得出了一个完整的解决方案，该方案在一阶光学和薄透镜的通常限制范围内适用于所有情况。主镜片和子镜片都可能是散光的。在通常情况下，有一个唯一的近用光学中心，但也可能出现没有近用光学中心或有无限多个近用光学中心的情况。系统地研究了这些情况。数值例子说明了该方法。
