The practitioner, while reviewing the basic principles of geometric optics essential for a proper understanding of ophthalmic refraction, often finds himself handicapped by lengthy decimal calculations. The fundamental properties of spherical lenses and mirrors are frequently lost in jumbles of compound fractions and long division.*
As an aid to physicians studying to become oculists, the following nomogram was devised to help eliminate the arithmetical drudgery of verifying optical bench experiments and to assist in visualizing the basic object-image relationships. The nomogram is easy to draw accurately, requiring only ruler and compass, or protractor.
Draw three straight lines passing through a common point, one vertical and the other two making angles of 60 degrees with the first (and with each other). Place arrows at the upper ends of the lines, and indicate, from left to right, p for object distance, f for principal focal distance, and q for image
ASKOVITZ SI. A Simple Nomogram for Problems in Optics. AMA Arch Ophthalmol. 1955;53(5):702-705. doi:10.1001/archopht.1955.00930010710014