Geometrical technique to determine the influence of monochromatic aberrations on retinoscopy

A geometrical-optical analysis is developed to predict the reflex observed in retinoscopy. The analysis can be expanded to explain the reflex for an eye with aberrations. The succession of reflexes across the pupil for each position of the retinoscope is represented in a contour plot. The plots demonstrate that retinoscopy can be considered a measure of the transverse ray aberration of the eye. For an eye with simple defocus this causes the typical with and against motions observed with hyperopic and myopic refractive errors. For an eye with aberrations we predict more-complex retinoscopic reflexes. This theory is confirmed by actual measurements on a human eye with known aberrations.