... Measurement of accommodation, gaze direction and pupil size Dynamic photorefractor measurements: In experiments 1, 2, and 3, accommodation, pupil size and gaze direction were measured objectively and dynamically ... induced by cognitive demand, the intended demand has to be validated by means of behavioral changes, i.e performance measures Increasing cognitive demand should result in increased performance times ... both indicators – pupil size and accommodation – with a simple video recording system is a tempting possibility, that additionally motivated this paper Cognitive demand can affect open-loop accommodation, ...