A BASIC computer program for schematic and reduced eye construction

A simple computer program for calculating schematic and reduced eyes is presented. The user supplies distances from the front of the eye and radii of curvature of refractive surfaces (anterior and posterior cornea and lens), distance to retina, and refractive indices of ocular media (cornea, aqueous, lens, vitreous). These values are input to calculate the necessary parameters for construction of a schematic and reduced eye, using Gaussian formulae and assuming a homogenous lens. The program produces powers of optical components and of the whole eye, cardinal points of the eye, and estimates of refractive state and retinal image size. These values may be printed in tabular form or plotted to scale with a graphics plotter. The program simplifies construction of schematic eyes by allowing rapid recalculation of the eye after changing one or more input parameters.