Fundamentals of Irregular Astigmatism and Clinical Research (5-1)　Higher-Order Aberration

Abstract

Trefoil and secondary astigmatism of higher-order aberration are introduced as the subject of the last in this series. It is reported that monocular triplopia and monocular diplopia are due to trefoil with spherical aberration and secondary astigmatism with spherical aberration, respectively. Here, the relation between these aberrations and defocus is shown using simulated retinal images. Also shown is that a special combination of trefoil and coma aberration is related to apparent accommodation.