ISO 9241-394:2020

Overview

ISO 9241-394:2020 specifies ergonomic requirements and recommendations to reduce visually induced motion sickness (VIMS) when watching electronic images. It applies to electronic display systems - including flat-panel displays, projectors with screens, and VR-type head‑mounted displays (HMDs) - but excludes HMDs that overlay electronic images on real-world scenes. The standard defines viewing contexts, guiding concepts, and basic conditions (see informative annexes) to help designers and content creators minimize nausea, dizziness, disorientation, and other biomedical effects.

Key topics and requirements

• Scope & context: Differentiates passive viewing (non-interactive playback) from active viewing (head-tracking or controller-driven, real‑time rendering).
• Major VIMS factors: Addresses visual global motion (types of rotation and translation), motion velocity, image size in the visual field, viewing duration, fixation/targeting, navigation velocity, predictive self-motion cues, and independent background motion.
• Ergonomic requirements: Provides minimal conditions and recommendations for image contents and display behavior to reduce VIMS (based on literature and Simulator Sickness Questionnaire-SSQ metrics such as SSQ total, nausea, and disorientation subscores).
• Measurement & conformance: Includes guidance on measurement methods (visual global motion, head-tracking time delay), conformance procedures, and reporting - enabling objective testing and verification.
• Mitigation methods: Annexes summarize practical countermeasures and assessment procedures, and discuss individual viewer factors and habituation effects.

Applications and practical value

ISO 9241-394 is practical for anyone designing, testing, or supplying electronic image systems and content where user comfort and safety are critical:

• VR/AR/immersive system developers: Optimize head‑tracking latency, motion rendering, and scene design to reduce motion sickness.
• Display manufacturers: Design HMDs, flat panels, and projectors with viewing conditions and latency performance that meet ergonomic recommendations.
• Content creators & game developers: Structure camera motion, field-of-view, and predictable self-motion cues to lower VIMS risk.
• Testing labs & safety officers: Use the standard’s measurement methods and SSQ-based guidance for compliance testing and risk assessment.
• Ergonomists & UX designers: Incorporate human-system interaction principles to improve user comfort across applications (training simulators, entertainment, remote operation).

Related standards

• ISO 9241 series (human‑system interaction) - broader ergonomics guidance.
• ISO 9241-392 - guidelines for stereoscopic 3D displays (methods relevant to HMDs).
• International Telecommunication Union (ITU) standards - generally govern broadcasting practices and may interact with content-distribution requirements.

Keywords: ISO 9241-394, VIMS, visually induced motion sickness, ergonomics, virtual reality, HMD, electronic displays, SSQ, display latency, viewing conditions.