The pupil near response is short lasting and intact in virtual reality head mounted displays

Abstract

The pupil of the eye constricts when moving focus from an object further away to an object closer by. This is called the pupil near response, which typically occurs together with accommodation and vergence responses. When immersed in virtual reality mediated through a head-mounted display, this triad is disrupted by the vergence-accommodation conflict. However, it is not yet clear if the disruption also affects the pupil near response. Two experiments were performed to assess this. The first experiment had participants follow a target that first appeared at a far position and then moved to either a near position (far-to-near; FN) or to another far position (far-to-far; FF). The second experiment had participants follow a target that jumped between five positions, which was repeated at several distances. Experiment 1 showed a greater pupil constriction amplitude for FN trials, compared to FF trials, suggesting that the pupil near response is intact in head-mounted display mediated virtual reality. Experiment 2 did not find that average pupil dilation differed when fixating targets at different distances, suggesting that the pupil near response is transient and does not result in sustained pupil size changes.

Technological Features of Immersive Virtual Reality Systems for Upper Limb Stroke Rehabilitation: A Systematic Review

“…Specifically, IVR can monitor the mobility and function of the upper limbs during the rehabilitation exercises without the necessity for external sensors, making it a less intrusive and more user-friendly option for both patients and clinicians [ 24 , 25 ]. Additionally, IVR systems have the capability to gather more physiological data, including autonomic responses, through techniques such as pupillometry to inform about pain and stress level of the patients [ 30 ].…”

Introduction to the Special Thematic Issue "Virtual Reality and Eye Tracking"

“…However, this approach requires the persistence of natural responses of the eyes to the (virtual) environment in VR displays. In the study "The pupil near response is short lasting and intact in virtual reality head mounted displays", Pielage et al (2023) experimentally examined the persistence of pupillary reflexes in VR; specifically, whether pupils show the expected constriction when virtual objects move closer to the user as they would in the real world. Greater pupil constriction was found to targets moving from far to near positions compared to targets moving from a far position to another far position.…”

“…They show how eye tracking in VR can be and has already been used to advance research in various fields, including research on the human visual system ( 2 ; 14 ) and cognitive processes ( 11 ; 17 ; 18 ), with important practical applications, for example in visual field examinations ( 13 ) and assessment of visual acuity ( 9 ; 10 ), military training ( 6 ) and for the development of new technological systems ( 7 ). Nevertheless, these articles also indicate there are still many open technical and methodological questions ( 5 ; 12 ; 15 ) that need to be addressed in future research to establish the required standards for scientific practice and an empirical basis for valid and reliable applications in various fields.…”