Oculomotor Response While Using a Helmet Display Incorporating an Accommodation-vergence Stress Reduction Algorithm

Study Overview
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Brief Summary
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Operational military personnel are increasingly using virtual or augmented reality headsets in the field or in training. However, these devices cause a conflict between accommodation (focus to see clearly) and vergence (alignment of both eyes on the object being viewed) that can be a source of visual fatigue and altered visual and perceptual abilities. Although techniques exist to limit this conflict for screen-based stimuli, the use of helmet visuals (or immersive headsets) adds technological complexity. Indeed, since accommodation on the screen of the helmet visual is impossible (i.e., distance too small) for the human visual system, lenses are used to virtually shift the image (referred to as a collimated image) so that accommodation can occur much further away. However, this material configuration also modifies the vergence, thus causing a conflict between accommodation and additional vergence that persists regardless of the attenuation technique used. In this study, the investigator proposed to modify the image display to take into account the technical features of the helmet to correct this techno-dependent conflict. This study is aimed at determining whether the setting recommended by the algorithm developed by the investigator limits visual fatigue better than the conventional setting recommended by manufacturers or a subjective setting controlled by the user.

Official Title
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Oculomotor Response While Using a Helmet Display Incorporating an Accommodation-vergence Stress Reduction Algorithm

Conditions
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Visual Fatigue

Intervention / Treatment
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* Other: Oculomotor tests


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age over 18 Non-presbyopic Stereoscopic acuity ≤ 60 min of arc Exclusion Criteria: Accommodative insufficiency (APP ≤ 13-age/4, in diopters) Accommodative inertia (+ and - block in binocular) Compensation by orthokeratology Present or past binocular pathology: strabismus or amblyopia

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Oculomotor tests|There will be four visits. Each visit is associated with a different exposure in terms of level of oculomotor conflict. At each visit, several oculomotor tests will be performed, followed by a comfort questionnaire. The oculomotor tests are subjective tests during which the participant will be asked to fix his/her eyes on one or more targets that can move in space and to indicate the way he/she perceives this/these target(s). Depending on the test, lenses may be inserted between the participant and the target to modify his/her perception. The comfort questionnaire consists to rate on a scale of 1 (not at all) to 5 (very much) the presence of visual symptoms, such as burning, watering or dryness. The participant will then have to perform four different perceptual tasks. His/her level of accommodation (i.e. focus) will be monitored throughout the tasks. Each exposure is followed again by eye tests and a comfort questionnaire.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evolution of oculomotor response to a stimulation generating jumps in vergence demand | Oculomotor response (accommodation and vergence) will be measured continuously via a single objective system (PowerRef 3) at each visit. | Until the end of the study (20 months) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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virtual reality