The circular symmetric point and the apalanatic point of spherical lens have one same expression,however the two kinds conjugate point are belong to difference category.

• 圆周的对称点与球透镜的齐明点虽然有一个相同的表达式,但这两类不同范畴的共轭点有着内在的差异,分析这种差异,有利于更好地理解它们。