-Recent advances in 3D technology have been accompanied by increasing complaints of visual fatigue. The usual explanation for such fatigue is that accommodation and convergence are mismatched during stereoscopic vision.The aim of this study was to measure fixation distances between lens accommodation and convergence in young subjects while they viewed real objects and 3D video clips. Measurements were made using an original instrument. The 3D video clips were presented to subjects using a liquid crystal shutter glass system. The results showed that when viewing real objects, the diopter values of subjects' accommodation and convergence were similar and changed periodically. This measurement method was thus considered to be appropriate for the measurement of stereoscopic vision. We also investigated lens accommodation and convergence when subjects viewed 3D video clips. Both accommodation and convergence were found to move along with the virtual position of 3D video clips. Therefore, there was little discrepancy between accommodation and convergence during the viewing of 3D images.

The interactions between various acyclic polyethers, RO(CH2CH2O)nR′(R, R′=CH3, Ph), and dimethyltin dichloride (DMTC) in aromatic solvents have been studied by means of 1H NMR spectroscopy. On the basis of a continuous variation method, the formation of the 1 : 1 complexes between glymes, CH3O(CH2CH2O)nCH3(n=2, 3, 4), and DMTC was revealed in benzene. The 2J(119Sn–CH3) values suggested distorted trans-octahedral configurations for these complexes. From the statistical consideration of stability constants, it was found that the coordination occurred virtually through neighboring two oxygen atoms in these complexes. DMTC gave the complexes of both 1 : 1 and 1 : 2 glyme/DMTC stoichiometry with glymes (n=5, 6) in benzene and with all glymes employed here in toluene and 1-chloronaphthalene. Coexistence of 1 : 1 and 1 : 2 species was also encountered for PhO(CH2CH2O)nCH3 (n=3, 4, 5), whereas no appreciable interaction was observed between PhO(CH2CH2O)nPh (n=2, 3, 4) and DMTC. On the basis of these observations, the additional formation of the 1 : 2 complexes was assumed to be caused by the bulkiness of polyethers.

Convergence, accommodation and pupil diameter were measured simultaneously while subjects were watching 3D images. The subjects were middle-aged and had weak hyperopia. WAM-5500 and EMR-9 were combined to make an original apparatus for the measurements. It was confirmed that accommodation and pupil diameter changed synchronously with convergence. These findings suggest that with naked vision the pupil is constricted and the depth of field deepened, acting like a compensation system for weak accommodation power. This suggests that people in middle age can view 3D images more easily if positive (convex lens) correction is made.

Equilibrium function in the cerebellum (vestibulo-cerebellar system) can deteriorate under the influence of alcohol. In the Romberg posture, the center of gravity, which was measured every 50 ms by stabilometry, appeared to shift with alcohol ingestion. In the previous study, a locus in the center of gravity (stabilogram) was converted to values of statistical indices such as area of sway, total locus length, and locus length per unit area, although these indices could not always distinguish between the statokinesigrams sampled from seven healthy young males in sober and intoxicated states. This measurement was made with an AMTI force plate. In this study, "translation error" was estimated in a d-dimensional embedding space in order to compare statokinesigrams recorded before and after the ingestion of doubly diluted brandy in 30 s (1 ≤ d ≤ 10). We succeeded in validating a stochastic differential equation as a mathematical model of the body sway. The randomness in the model was preserved after alcohol intake and significantly increased in the medial/lateral direction. Visual information referred by the postural control system when standing might be interfered by the effects of intoxication, which was regarded as disturbance. This method is considered to be useful to diagnose the disorders of the vestibulocerebellar system.

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