Prismatic Effect and Visual Acuity Degradation

ABSTRACT

Prisms have been used as tools with which to treat and diagnose many diseases in strabismology. But, because of prismatic distortion and dispersion, the visual acuities are declined. The purpose of this study is to show the relationship between prismatic effect and visual acuity degradation. Visual acuities were measured through a series of prisms of CR-39 to quantify the blur induced by prism. The mean visual acuities of myopias and amblyopias(with or without correction), and emmetropias were reduced as prism diopters were increased. The declines were linear. There was no significant difference among the declines of visual acuities of each group. Whenever to prescribe prisms and to test with prisms, we should remind that prisms could reduce visual acuities.