ISO 9241-392:2015

Overview

ISO 9241-392:2015 - Ergonomic recommendations for the reduction of visual fatigue from stereoscopic images - provides guidance to reduce visual discomfort and visual fatigue when viewing stereoscopic images under defined viewing conditions. The standard addresses the optical and perceptual causes of fatigue that arise from binocularly presented, disparate images and applies to both stereoscopic image content and displays (glasses-based, two-view autostereoscopic, head‑mounted displays, and projectors). Annex B (viewing conditions) and Annex C (informative numerical criteria) support practical assessment and implementation.

Key Topics and Technical Requirements

• Guiding concepts and framework for comfortable stereoscopic viewing, based on human visual system limits.
• Viewing conditions: design viewing distance and interpupillary distance considerations for content and device layout.
• Interocular geometrical differences:
  • Vertical misalignment
  • Rotational misalignment
  • Interocular magnification differences
• Interocular photometric differences:
  • Luminance, contrast and chromaticity mismatches between left/right images
• Interocular photometric interaction:
  • Crosstalk (ghosting) and its ergonomic effects
• Accommodation–convergence mismatch: recommendations to limit conflicts between eye focus (accommodation) and eye alignment (vergence) that often cause fatigue.
• Other factors: global motion, content editing and presentation strategies that influence viewer comfort.
• Assessment and reporting: practical guidance on how to use the recommendations, test applicability, and document conformance (see Annex E for a sample procedure).
• Numerical guidance: Annex C provides informative numerical values to assist assessments (not normative).

Practical Applications and Who Uses It

ISO 9241-392 is intended for professionals responsible for the design, development and supply of stereoscopic systems and content, including:

• Display manufacturers (HMDs, autostereoscopic displays, projectors)
• VR/AR headset designers and system integrators
• Stereoscopic content creators (film, medical imaging, simulation)
• User-experience and ergonomics specialists
• Test labs and procurement teams specifying ergonomic acceptance criteria

Practical uses include reducing viewer fatigue in medical visualization, industrial training, entertainment, and virtual collaboration; defining test methods and product requirements; and improving user comfort through design choices (viewing geometry, photometric uniformity, crosstalk control).

Related Standards

• ISO 9241 series (human–system interaction) - broader ergonomics guidance
• ISO 9241-303:2011 - Requirements for electronic visual displays (see Annex E for virtual displays/HMD guidance)
• ISO/TR 9241-331 - Autostereoscopic display optical characteristics (related guidance)
• ITU broadcasting recommendations where stereoscopic broadcast interoperability is required

For implementation, consult the full ISO 9241-392:2015 text for detailed wording, informative numerical references in Annex C, and recommended test procedures in Annex E.