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HUD elements occupy the visual field

The binocular horizontal visual field is far larger than the region of resolvable detail

Monocular viewing or pathological visual field defects reveal the blind-spot effect

The visual field automatically splits into figure and ground

Being in the visual field is not the same as being seen

Binocular field overlap keeps the blind spot unnoticed in daily life

The effective field of view is the small area content can be identified in during one fixation

Field of view shapes immersion and peripheral awareness

There are no photoreceptors where the optic nerve exits, creating a physiological blind spot

Viewing distance directly changes how much content the effective field of view covers

High-contrast scenes create competing demands on pupil size, producing local over- or under-exposure

Low-frequency flicker carries a risk of triggering photosensitive reactions

Information should appear and fade with the current phase

Some people still consciously notice flicker beyond conventional thresholds; individual variability is large

Emotional elements cost attention, not just time

Local adaptation completes faster than overall light/dark adaptation

Flicker above a critical rate is perceived as steady

Some visual features are processed in parallel before attention is allocated

Large translations and scales readily cause discomfort

Sudden starts are a major source of discomfort

HUD placement should follow information viewing frequency

Label and field must be associated in the accessibility tree

Magnification shrinks the visible field to a tiny viewport

Attention occupied elsewhere means even obvious objects go unseen

Light, sound, and projection can supplement intent

A placeholder vanishes once typing starts, so it cannot serve as a label

Collision risk needs in-game warnings

Interface elements outside the effective field of view require an eye or head movement

Angles near horizontal or vertical are judged more accurately than oblique ones

Voice and head-worn displays are primary alternatives

Under high stress, attention narrows to a single information source

Critical information should not fall exactly on the blind-spot angle in monocular-use scenarios

Immersion and information completeness trade off

Attention is consumed when figure-ground is ambiguous

Occluding one eye does not switch off its input, and rivalry can still occur

Large, high-contrast flashes are the highest risk

The saccade is a fast, ballistic eye movement used to shift the point of fixation

Cascades are a poor fit when levels must be compared

Color discrimination drops sharply in peripheral vision

Wrist-raise angle limits the visible region

Smooth pursuit follows a continuously moving target and needs the target itself to be moving

Color, orientation, size, and motion are reliable preattentive channels

The spread of spatial attention can narrow or widen like a spotlight

Peripheral vision has low resolution but is sensitive to motion and luminance change

Handoff must carry state

Overlays need a clear figure-ground relationship with what's beneath

Start and end dates need comparison in one view

Having both beats choosing one

The current holder of control must be persistently visible

High-saturation colour jumps the queue