Infrared Eye Tracker Research Articles

Eyetracker analysis of fixation points using an IR HUD in an automobile

This paper describes the experimental apparatus and analysis techniques now in place at the US Army Tank-automotive and Armaments COMmand Visual Perception Lab in Warren, Michigan, and the results of some preliminary trials using these methods. The tools will be used to develop and analyse experiments to better understand how drivers use various displays and viewing systems intended to aid drivers in poor visibility conditions, particularly at night. Visible and infrared road scene imagery obtained from the field were displayed simultaneously and subject eye fixation and point of gaze measured using a magnetic head tracker and near infrared eyetracker. Results were analysed to determine if personal differences between the various subjects caused them to prefer one display to another. The goal was to see if people prefer to use the heads up display or the direct view for driving at night.

Eye movement impairment and schizotypal psychopathology

Eye movement dysfunction in relation to a smooth pursuit task has been documented in schizophrenic patients and in patients with the related personality disorder, schizotypal personality disorder. To investigate which quantitative measures are associated with the eye movement dysfunction and whether the dysfunction is more related to the psychotic-like or the deficit-like symptoms of schizotypal personality disorder, ratings of eye movements in several groups of subjects were compared. The study groups consisted of 26 patients with schizotypal personality disorder, 42 patients with other personality disorders (22 who also had two or more schizotypal personality traits and 20 who had fewer than two), and 37 normal comparison subjects. Smooth pursuit eye tracking of sinusoidal and constant velocity targets was recorded by an infrared eye tracking system. Two raters evaluated pursuit gain and large and small saccades in the direction of the target and in the direction opposite to that of the target (quantitative ratings) and constant velocity (qualitative rating). Patients with schizotypal personality disorder and patients with other personality disorders and two or more schizotypal traits, but not those with fewer than two schizotypal traits, had significantly poorer qualitative ratings of tracking than the normal comparison subjects. Neither gain nor any of the saccadic measures significantly differed between groups. The number of large saccades in the direction of the target was the only quantitative variable that predicted low qualitative ratings. Qualitatively poor tracking was associated with the deficit-like, but not the psychotic-like, symptoms of schizotypal personality disorder. Patients with schizotypal personality disorder demonstrate qualitatively poorer tracking than comparison groups, and the impaired tracking is associated with deficit-like symptoms.

Vergence Movements in Comitant Strabismus

Vergence movements induced by base-out prisms were recorded, with an infrared eye tracker, for 6 patients with comitant esotropia (i.e., convergent strabismus) and anomalous retinal correspondence and for 6 normal subjects. Vergence movements of strabismic subjects were much slower and showed characteristics different from those of controls. It may be argued that vergence movements are induced by disparity and represent the motor fusion component left over in strabismus. In fact, in this study accommodative as well as proximal vergence had been ruled out. Therefore, the movements recorded can be considered the objective representation of the well-known phenomenon of prism compensation or adaptation, found in many strabismic patients.

Smooth pursuit eye tracking dysfunction and negative symptoms in schizophrenia

This study examined the hypothesis that negative symptoms are associated with abnormalities of smooth pursuit in schizophrenic patients. The pursuit eye movements of 25 subjects with schizophrenia and 25 matched normal control subjects were recorded using an infrared eye tracking system and quantified using the log of signal-to-noise ratio (1n S/N). The severity of negative symptoms within the schizophrenic group was rated using the Scale for the Assessment of Negative Symptoms. Previous findings of pursuit abnormalities among schizophrenic patients as a group were replicated. There was, however, no significant association between the eye tracking dysfunction and the severity of negative symptoms.