Accommodative response under reduced visual conditions

Abstract

To investigate the effects of luminance and visual depth cues on accommodation, the accommodation with decreased luminance was measured with a laser optometer under three visual conditions, a target in a full-cue visual field, a target in a dark room, and in an empty visual field without target. Four persons of 21 to 27 years old, with normal uncorrected visual acuity, served as subjects. The accommodation increased with decreased luminance in the fullcue visual field. In the empty visual field, however, the accommodation remained constant on a high level regardless of luminance levels. The results suggest that night myopia can be explained by the effect of reduction of depth cues caused by decreased luminance rather than the effect of luminance alone. There was no significant difference in accommodation between in the total darkness and in the bright empty field, and the mean accommodation under reduced cue conditions was found to be 2.06 diopters (focal distance was 49 cm).

An Empirical Demonstration of the Interactive Influence of Distance and Flatness Information on Size Perception in Pictures

“…There is no binocular disparity provided by the various objects portrayed in the picture; thus stereopsis indicates that all points in the picture are equidistant from the observer. The degree to which accommodation and vergence function to indicate depth and distance is still controversial (e.g., Brenner & Van Damme, 1998;Foley, 1978Foley, , 1980Iida, 1983;Leibowitz & Moore, 1966, Leibowitz, Shiina, & Hennessy, 1972, but to the extent they do so they indicate that the surface of the picture is flat. A picture typically has clearly visible Figure 1.…”

The Cumulative Influence of Depth and Flatness Information on the Perception of Size in Pictorial Representations

“…There is no binocular disparity; thus stereopsis shows the two boards to be equidistant. To the extent that accommodation and vergence function to indicate distance (and their importance for such a role is still the subject of controversy; see Brenner & Van Damme, 1998;Foley, 1978Foley, , 1980Iida, 1983;Leibowitz & Moore, 1966), they signal equal distances for the two boards. In addition, a painting has boundaries, is usually mounted on a wall, and is presented in a context where the observer's expectations are that he/she will be looking at a flat picture.…”