This paper describes recent advances in three-dimensional display systems. Some of the problems facing stereoscopic display are pointed out from the aspect of human visual perception. The main problems include visual fatigue arising from the conflict between vergence and accommodation, and the lack of motion parallax stemming from the display of only right and left images. It is observed that the flipping caused by use of the uncontinuous image display method persists even after using multiview stereoscopic images. Also described are recent developments in three-dimensional display systems that can eliminate imperfections in stereoscopic display. The possibility of using these systems to eliminate visual fatigue and flipping is examined on the basis of the experimental results obtained. Further, the common principle underlying these displays is explained by taking into account the basic method of light field reproduction. Finally, three-dimensional displays are introduced. These three-dimensional displays are designed based on each intend purpose, and also selected how to use both horizontal and vertical disparities or only horizontal disparity. The first is a cubic-type display that can be moved by hand and can display horizontal and vertical disparities in a manner similar to that of integral photography. The second is a tabletop-type display that can display only horizontal disparity, without flipping. The third is a large-screen three-dimensional display that only uses horizontal disparity to maintain high picture quality.
Saccadic eye movements bring the image of a visual target onto the fovea. Because of the small size of the fovea, saccades must be accurate, and in fact they are. Their accuracy is maintained by a motor learning mechanism called saccade adaptation, which is driven by visual information about movement error. The McLaughlin paradigm, which creates artificial movement error, has proven to be a valuable experimental tool for inducing adaptation and has revealed various aspects of saccade adaptation. Most importantly, the cerebellar oculomotor vermis has been implicated as a site of saccade plasticity. However, little is known about the neural signal that drives and guides motor learning in voluntary movements, including saccades. This review first summarizes our current knowledge regarding saccade adaptation, then describes the authors’ recent research on the induction of adaptation by electrical stimulation of the midbrain superior colliculus. Long known to be a structure that generates saccade motor commands, the superior colliculus is now suggested to be a brainstem origin of a neural signal that drives saccade motor learning.
Purpose: In psychophysics, it is said that logarithmic (Log) visual acuity (VA) can be illustrated by normal distribution. We developed a statistical method for evaluating VA changes in an individual.
Methods and Results: LogVA and standard deviation (SD) were calculated by logistic regression. We assessed the change in VA using the χ2-test. We tested 1 individual with no visual abnormalities in order to assess the accuracy of this statistical evaluation method. LogVA was 0.368±0.021 in complete refractive correction and 0.243±0.016 in +0.50D incomplete refractive correction. We statistically evaluated the decrease in VA.
Conclusion: Heretofore, change in VA had not been assessed on a scientific basis in an individual. However, we calculated LogVA±SD by logistic regression and evaluated it using Nagai’s test of significant difference.