Visual stimuli that isolate pupil color and pupil grating responses in human vision have been used to investigate the properties, of stimulus-specific pupil responses in the rhesus monkey. We measured and compared pupil responses to light flux increments, isoluminant chromatic stimuli, and gratings of equal and lower space-averaged luminance. The parameters investigated were luminance contrast ...

background : patients with alzheimer's disease (ad) reportedly hibit hypersensitivity to much diluted tropicam solution (0.005%), a m4 muscarinic receptor antagonist. therefore aocular application of 0.005% tropicamide ma be useful for screening dementia. the aim of this study was to simplify the pupil response test by using a new image analyzing system, which consists of a cheap, simple, and e...

Changes in pupil diameter can reflect high-level cognitive signals that depend on central neuromodulatory mechanisms. However, brain mechanisms that adjust pupil size are also exquisitely sensitive to changes in luminance and other events that would be considered a nuisance in cognitive experiments recording pupil size. We implemented a simple auditory experiment involving no changes in visual ...

Pupil diameter is enhanced in a variety of emotional contexts, including viewing pictures, listening to sounds, and during threat of shock. In this study, we investigated pupil diameter changes during emotional imagery. Participants imagined scenes describing pleasant, unpleasant, or neutral events while pupil diameter was continuously recorded. Second by second changes in pupil diameter were a...

Utilizing the EMR-8B eye-tracker system, the pupil changes of eight drivers were monitored when they drove through 26 typical highway tunnels. Based on the test results, the driver’s pupil areas and pupil illuminance were found to be in a power function relationship at tunnel entrances. Furthermore, a quantitative relationship between the pupil area and its critical velocity was established, an...

Determining the pupil center is fundamental for calculating eye orientation in video-based systems. Existing techniques are error prone and not robust because eyelids, eyelashes, corneal reflections or shadows in many instances occlude the pupil. We have developed a new algorithm which utilizes curvature characteristics of the pupil boundary to eliminate these artifacts. Pupil center is compute...