Accommodation to Stimuli in Peripheral Vision

Can targets in peripheral vision elicit accommodation responses? We used a laser optometer to measure monocular steady-state accommodation for stimuli at retinal eccentricities ranging from 1 degree to 30 degrees. The optical distance from the eye to the stimulus was varied from 0 to -6 D by introducing lenses in front of the eye. The accommodative response was plotted as a function of optical distance to produce an accommodative stimulus-response function. The magnitude of accommodative response was defined as the difference between the maximum and minimum values of this function. The magnitude declined from 4 D at 1 degree to 1-2 D at 30 degrees eccentricity. The relation of the magnitude of accommodative response in peripheral vision to changes in acuity, contrast sensitivity, and depth of focus are considered. The role played by convergence accommodation is also discussed.