Effects of monochromatic and chromatic oblique aberrations on visual performance during spectacle lens wear.

An optical system is described which allows overall visual performance to be studied when the wearer of a spectacle lens views objects through the lens periphery. Performance with lenses of any refractive power can be explored without any need for subjects to have the appropriate complementary refractive errors. In comparison with the effects of dioptric defocus, transverse chromatic aberration (TCA) is found to cause a relatively greater degradation in contrast sensitivity at high spatial frequencies when tangentially-oriented gratings are observed. The relative importance of TCA appears to have been underestimated in some previous studies. As vision is found to be affected by both TCA and defocus, a careful compromise between chromatic and monochromatic aberrations is required.