Does target orientation influence the accommodative response?

A number of studies have demonstrated that visual responsivity is optimum when viewing either horizontal or vertical stimuli but is significantly reduced when viewing an obliquely oriented object of regard. Accordingly this study examined the accommodative response in 10 subjects to targets oriented at 45, 90, 135 and 180 degrees to the horizontal. Stimuli were located at distances of 1, 3 or 5 D, and steady-state accommodation was measured subjectively from the right eye using a Hartinger coincidence optometer. The data indicate that, for high contrast, supra-threshold targets, variation in target orientation did not produce any significant change in accommodative response. These results suggest that neural sensitivity for monocular blur-driven accommodation is orientation independent. This finding would imply that accommodation and contrast detection are mediated by dissimilar processes. [ABSTRACT FROM AUTHOR]