The effect of a peripheral stimulus on accommodation

Accommodation was measured by the laser scintillation technique while the S viewed a stationary fixation spot through a series of apertures in a screen located at various distances. The magnitude of accommodation was a compromise between the distance of the fixation spot and the screen. Accommodation was affected significantly by the interaction of the distance of the screen with aperture sizes of 1 and 4 deg and distance of the screen with its order of movement from near to far or far to near. The data are interpreted as implying the importance of the peripheral visual field and/or perceptual factors when conflicting cues to distance coexist in the visual field.