Dependence of accommodation response on the spatial frequency spectrum of the observed object

Abstract Experiments are described in which the monocular, steady-state, accommodation response to sinusoidal grating targets was assessed as a function of the spatial frequency of the grating and its vergence at the eye, using a laser optometer. At all levels of stimulus, the response is found to be dependent upon the grating frequency. At very low spatial frequencies the response is often substantially in error and is closely related to the accommodation exercised by the observer when viewing an empty field. At higher frequencies the response becomes more accurate and its exact value is probably dependent upon the observing conditions and upon the ocular aberrations and. other properties of the observer. Further experiments with Snellen targets suggest that the accommodation to a target with a complex spatial frequency spectrum cannot be predicted from a knowledge of that spectrum and of the observer's response to its component frequencies, under the same viewing conditions. The significance of the findings to theories of accommodation is indicated.