Effect of ocular transverse chromatic aberration on detection acuity for peripheral vision.

Abstract

We examined the effect of transverse chromatic aberration (TCA) on detection acuity for white-light interference fringes seen in Maxwellian view at various orientations and locations in the visual field. A circular patch (3.5° diameter, 3.2 log Trolands) of nominally high-contrast fringes was produced on the retina by a commercial instrument (the Lotmar Visometer, Haag Streit) mounted on a gimbal for controlled positioning of the stimulus in the visual field from 0° to 35° eccentricity. Detection acuity for white light fringes for all meridians and eccentricities ≥15° was maximum when fringes were oriented parallel to the visual meridian line. This meridional effect disappeared when a narrow-band filter was used to eliminate TCA. The meridional effect also disappeared when the interferometric stimulator was displaced laterally to align the instrument with the eye's local achromatic axis. Modelling confirmed that TCA is the major factor responsible for white-light meridional bias, with minor contribution arising from higher-order monochromatic aberrations and neural factors.