It is not uninteresting to compare the refraction of an eye in possession of its lens with the refraction that it would have when deprived of it; in other words, to compute from the refraction of the complete eye that of this eye in a condition of aphakia, and vice versa. Urged by some friends to make more generally known the way we follow in calculation, we publish it here, hoping that by its simplicity and clearness it may find the approval of our learned colleagues.
Reference: Landolt E. Determination of the presumable refraction of the eye with and without its crystalline lens. Arch Ophthalmol. 1901;30:467.