Age-Related Dynamics of Discrimination of the Orientation of Rectangular Gratings at the Resolution Limit of the Visual System

The visual acuity of 215 observers between the ages of 3 and 20 years was measured by determining the minimal size of rectangular gratings, when the observer could discriminate horizontal and vertical gratings. The study of the influence of similar surrounding patterns on the assessment of visual acuity was conducted in parallel. The visual acuity was shown to increase with age and to reach the level typical of adults at about 11 years. All the observers had impaired discrimination of the orientation of gratings when the surrounding gratings were arranged close to each other. The distances at which the impairment occurs gradually decrease with increasing age up to 20 years from 2.75 to 1.5–0.75 periods of the test frequency. The problem of the formation in ontogenesis of possible mechanisms ensuring visual acuity and the ability to perform the task of objects' segmentation from the surrounding is discussed.