Atmospheric turbulence causes twinkling of stars and diminishes the clarity of telescopic vision. We developed adaptive optics systems for the 8m Subaru Telescope atop Mauna Kea, Hawaii, to overcome this problem for ground-based telescopes. To make use of the adaptive optics system easier, we developed a laser guide star generation system to make an artificial star in the upper atmosphere, using a power laser beam, to measure atmospheric turbulence. The basic principles of these high-tech systems, the scientific story of the discovery of the most distant galaxy, 12.9 billion light years distant, and a project for constructing an even larger 30m telescope are shown using images and visual drawings.
Measuring the near triad of the two eyes simultaneously is one method of evaluating 3D displays. Discrepancy of accommodation and vergence or blur in retinal images could be expected during certain kinds of 3D displays; this may be related to fatigue or other physiological problems. In this article, I explain two methods of measuring the near triad. I also explain aberration measurement, and its merit.
Depth of field (apparent accommodation) of aphakic eyes corrected with spectacles, contact lenses (CLs), spherical intraocular lenses (IOLs) and aspheric IOL were computed by convoluting optotype with a point spread function calculated by the Fresnel-Kirchhoff integral from wave aberration obtained via ray tracing. The square root of wave aberration (P-V value) correlated well with depth of focus. Depths of field calculated from depths of focus and the values obtained using the varied spectacle power method were almost equal. When exit pupil size was approximately 3.5mm and visual acuity was 20/20, depth of field with spectacles, CL, spherical IOL and aspheric IOL were 0.40, 0.85, 0.55 and 0.30D, respectively. When entrance pupil size was around 1.5mm, depth of field had maximum value. When entrance pupil size was larger than 1.5mm, depth of field decreased, the value with aspheric IOL becoming half that with spherical IOL.
Previous studies have shown that visual attention either facilitates or inhibits the higher-level processes of visual information. However, it is not clear whether visual attention modulates the early level processes of the visual system. The present study aims at revealing whether visual attention independently affects luminance and chromatic channels, which are assumed to be in the early level of the visual system. In experiments, we measured the contrast detection sensitivities of chromatic and luminance responses to foveal stimulus and peripheral stimulus in the dual task paradigm, and observed whether the contrast sensitivity of the luminance and chromatic channels varied in a different manner between central priority and peripheral priority conditions. We found that visual attention increased contrast sensitivity in the chromatic and luminance channels, but in the same way between different priority conditions. Results were not sufficient to reveal whether visual attention independently affected the luminance and chromatic channels, but suggested that the temporal condition of stimulus presentation should be considered, to observe the effects of attention on the early level processes of the visual system.