Accommodation as a function of object form.

The steady-state, monocular accommodation resposne 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 accommodative stimulus, the response was found to be dependent on grating frequency. At very low frequencies, the response was often substantially in error and was closely related to the accommodation exercised by the observer when viewing an empty field. At higher frequencies, the response became more accurate. Possible models for accommodative strategies underlying the experimental results are discussed. A model involving dynamic evaluation of the changes in retinal-image modulation produced by accommodation fluctuations for many features of the observations.