Pupil size is known to correlate with the changes of cognitive task workloads, but how the pupil responds to requirements of basic goal-directed motor tasks involved in human-machine interactions is not yet clear. This work conducted a user study to investigate the pupil dilations during aiming in a tele-operation setting, with the purpose of better understanding how the changes in task requirements are reflected by the changes of pupil size. The task requirements, managed by Fitts' index of difficulty (ID), i.e. the size and distance apart of the targets, were varied between tasks, and pupil responses to different task IDs were recorded. The results showed that pupil diameter can be employed as an indicator of task requirements in goal-directed movements-higher task difficulty evoked higher valley to peak pupil dilation, and the peak pupil dilation occurred after a longer delay. These findings contribute to the foundation for developing methods to objectively evaluate interactive task requirements using pupil parameters during goal-directed movements in HCI.

Pupil size is known to correlate with changes of cognitive task workloads, but the pupillary response to requirements of basic goal-directed motor tasks is not yet clear, although pointing with tools is a ubiquitous human task. This work describes a user study to investigate the pupil dilations during aiming in two tele-operation tasks with different target settings, one aiming at targets with different sizes located at constant distance apart, and the other aiming at targets varying in different distances. The task requirements in each task were defined by Fitts' index of difficulty (ID). The purpose of this work is to further explore how the changes in task requirements are reflected by the changes of pupil size, i.e., whether the pupil responds to either target size or target distance, or to both of them. Pupil responses to different task IDs were recorded in each task. The results showed that the pupil responds to the changes of ID, not just to the change of target size. This implies that pupil diameter can be employed as an indicator of task requirement in goal-directed movements, because higher task difficulty evoked higher peak pupil dilation which occurred with longer delay. These findings can be used for detailed understanding of eye-hand coordination mechanisms in interactive systems and contribute to the foundation for developing methods to objectively evaluate interactive task requirements using pupil parameters during goal-directed movements.

Novices were trained to perform a unimanual peg transport task in a laparoscopic training box with an illuminated interior displayed on a monitor. Subjects were divided into two groups; one group was verbally instructed to direct their gaze at distant targets, while the other group had their gaze behaviour implicitly manipulated using distant target illumination. Both groups achieved similar task completion times post-training and developed peripheral vision strategies leading to delayed foveation on targets until the instrument was closer to its destination, although the ability to focus on targets earlier during manual movements as done by an expert surgeon was quickly regained by the verbal instruction group post-training. This suggests that care should be taken when employing visual attention cuing methods such as target highlighting for training eye-hand coordination skills, as simple verbal instruction may be sufficient to help trainees to adopt more expert-like gaze behaviours.

To observe whether there is a difference in eye gaze between doing a task, and watching a video of the task, we recorded the gaze of 17 subjects performing a simple surgical eye-hand coordination task. We also recorded eye gaze of the same subjects later while they were watching videos of their performance.

For gaze-based training in surgery to be meaningful, the similarity between a trainee's gaze and an expert's gaze during performance of surgical tasks must be assessed. As it is difficult to record two people's gaze simultaneously, we produced task videos made by experts, and measured the amount of overlap between the gaze path of the expert surgeon and third-party observers while watching the videos. For this investigation, we developed a new, simple method for displaying and summarizing the proportion of time during which two observers' points of gaze on a common stimulus were separated by no more than a specified visual angle.

The study of surgeons' eye movements is an innovative way of assessing skill and situation awareness, in that a comparison of eye movement strategies between expert surgeons and novices may show differences that can be used in training.

A real-time eyegaze selection interface was implemented using a Tobii eyegaze tracking monitor. A hierarchical button menu was displayed on the screen and specified selections were made by eyegaze fixations and glances on the menu widgets. The initial version tested three different spatial layouts of the menu widgets and employed a dwell + glance method of selection. Results from the pilot interface led to usability improvements in the second version of the interface. Selections were activated using a glance + dwell method. The usability of the second study interface received a positive response from all 8 participants. Each selection gained more than a 100% speed increase using the revised interface.