PubMed HealthSearch

Biomedical subjects

D Shirachi

Publications and source records attributed to D Shirachi.

2 recordsLinked to original sources

Accommodation dynamics I. Range nonlinearity.

We show the presence of a new nonlinearity in accommodation dynamics. Positive accommodation is slower when the eye is operating in the near range; conversely, relaxation of accommodation is apparently slower during work in the far range. Latency of accommodation is unaffected by working range. This new dynamic range nonlinearity has been defined in connection with a continuing research study of accommodation responses in normal subjects and in clinic patients. Instrumentation and analysis procedures are described.

Accommodation, Ocular

Dynamic measures of vergence accommodation.

Dynamic measures of vergence accommodation (VG-ACC) are necessary for complete analysis of the triadic near response but are difficult to obtain because eyeball rotation affects accommodative measures. A dynamic optometer that uses the third Purkinje image is shown to be insensitive to small eye rotations and permits dynamic measures of VG-ACC responses. Such measures are presented to demonstrate the feasibility of this method. Average latency measures of 260 msec for VG-ACC fall between the latency of 160 msec for disparity vergence and the latency of 380 msec for accommodation. Additional dynamic features of VG-ACC resemble those of other components of the near triad.

Accommodation, Ocular