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Biomedical subjects

H Ohzu

Publications and source records attributed to H Ohzu.

10 recordsLinked to original sources
PubMed1989

Human visual spatio-temporal frequency performance as a function of age.

Deterioration of human spatial frequency contrast sensitivity with increasing age was measured, for both stationary and drifting gratings, by producing interference fringes directly on the subject's retinas. There were losses at high spatial frequency up to 40 years of age, and losses at all spatial frequencies thereafter. Older subjects exhibited better than expected performance for drifting low spatial frequency gratings. These results are consistent with the differential effects of aging on different populations of visual neurons.

Adult↗
PubMed1982

Electrical stimulation of skin for information transmission--III: sequential signal transmission.

The transmission of sequentially discrete coding signals such as Morse Code from machines to human beings by means of skin sensation was tested by electrical stimulation of skin. Here, the temporal response of skin sensation to electrical stimulation of skin is a very important factor. In this study, the temporal characteristics of skin sensation when transmitting sequential signals were examined and two modulation methods of electrical stimulation of skin were evaluated. One uses a coaxial electrode with temporal modulation and the other uses a coaxial electrode array with spatio-temporal modulation. It has been found that temporally sequential signals are recognized with higher accuracy with spatio-temporal modulation than with temporal modulation. Information transmission performance was also quantitatively analyzed using the Information Theory.

Electric Stimulation↗
PubMed1979

Contrast (modulation) sensitivity functions measured in patients with high refractive error with emphasis on aphakia: I. Theoretical considerations.

Recently, alterations in contrast (modulation) sensitivity functions of patients with high refractive errors have been noted. For example, this seems to be a common finding in aphakia. In some measure the observed alterations are due to the effect of the corrective lens and the optics of the eyes. These optical effects (in addition to blur) must be factored out in order to determine whether residual effects on the visual system remain. The argument is applicable to photographs of sine wave fringes as well as devices designed to produce interference patterns directly on the retina. A simple means for largely correcting these lens effects is discussed.

Aphakia↗