Cognitive effort is reflected in pupil dilation, but the assessment of pupil size is potentially susceptible to changes in gaze position. This study exemplarily used sentence reading as a stand-in for paradigms that assess pupil size in tasks during which changes in gaze position are unavoidable. The influence of gaze position on pupil size was first investigated by an artificial eye model with...

During wakefulness, pupil diameter can reflect changes in attention, vigilance, and cortical states. How pupil size relates to cortical activity during sleep, however, remains unknown. Pupillometry during natural sleep is inherently challenging since the eyelids are usually closed. Here, we present a novel head-fixed sleep paradigm in combination with infrared back-illumination pupillometry (iB...

BACKGROUND Pupil size is an important factor in predicting post-operative satisfaction. We assessed the correlation between pupil size, measured by Humphrey static perimetry, and various affecting factors in patients with glaucoma. METHODS In total, 825 eyes of 415 patients were evaluated retrospectively. Pupil size was measured with Humphrey static perimetry. Comparisons of pupil size accord...

PURPOSE To determine whether there are systematic changes in pupil location with changes in the state of pupil size and with other ocular variables. METHODS High-resolution images of the pupil of the eyes of 70 subjects were taken using an infrared-sensitive camera. Images were obtained under mesopic, photopic, and pharmacologically dilated conditions. From the images, the center and diameter...

BACKGROUND Early detection of pupillary changes in patients with head injuries can alert the care team to increasing intracranial pressure. Previous research has shown inconsistencies in pupil measurement that are most likely due to the subjective nature of measuring pupils without the assistance of technology. OBJECTIVES To evaluate nurses' abilities to assess pupil diameter accurately and d...

BOTH hypotheses and conclusions relating teacher-pupil behavior to pupil growth tend to be stated in simple, declara tive sentences, as: "Increased teacher indi rectness is associated with increased pupil growth in subject matter and more favor able attitudes"; or, "Decreased teacher criti cism is associated with more favorable pu pil attitudes and increased subject-matter growth." Yet probably...

We investigate the gaze estimation error induced by pupil size changes using simulated data. We investigate the influence of pupil diameter changes on estimated gaze point error obtained by two gaze estimation models. Simulation data show that at wider viewing angles and at small eye-camera distances, error increases with increasing pupil sizes. The maximum error recorded for refracted pupil im...

Pupil size, as a component of orienting, changes rapidly in response to local salient events in the environment, in addition to its well-known illumination-dependent modulation. Recent research has shown that visual, auditory, or audiovisual stimuli can elicit transient pupil dilation, and the timing and size of the evoked responses are systematically modulated by stimulus salience. Moreover, w...

A photometric study of the effect of pupil dilatation on Nd:YAG laser iridotomy area was performed in 21 eyes of 21 patients. The iridotomy area was 0.075 (0.055) mm-2 (mean (SD)) before pupil dilatation and 0.073 (0.070) mm-2 after pupil dilatation (t test NS). Iridotomy area after pupil dilatation correlated with iridotomy area before pupil dilatation (r = 0.815, p < 0.01) but did not signifi...

the purpose of this study was to evaluate the effects of a combination of latanoprost and pilocarpine onthe intraocular pressure in experimentally glaucomatous rabbits. ocular hypertension was induced in 11conscious rabbits by the oral administration of tap water (70 ml/kg) via an orogastric tube. the study wasconducted in three therapeutic groups to test the effects of latanoprost (group l), p...