Visual acuity measured with pupil responses to checkerboard stimuli.

The response of the pupil was measured to a foveally fixated small field in which checkerboards were alternated with a blank field of equal average luminance. The subjects studied had refractive errors, but their eyes were free from pathological changes. A pupil visual acuity could be derived, which showed a very high correlation with the subjective acuity with the same checkerboard stimuli. The method of obtaining pupil visual acuity seems to compare favorably with other objective methods of measuring visual acuity.