The precision of gaze. A review

Area of Science:

• Ophthalmology
• Neuroscience
• Human Factors Engineering

Background:

• Accurate gaze fixation is crucial for visual perception.
• Technological advancements enable precise measurement of gaze stability.
• Understanding gaze stability under natural conditions is essential for visual science.

Purpose of the Study:

• To review current knowledge on human gaze stability during object fixation.
• To assess the impact of head mobility on gaze precision.
• To evaluate the implications of gaze imprecision for monocular and binocular vision.

Main Methods:

• Review of recent studies measuring gaze accuracy with head-free conditions.
• Comparison of gaze stability in rigidly held versus free-moving heads.
• Analysis of psychophysical evidence regarding visual perception under gaze imprecision.

Main Results:

• Gaze stability is halved when the head is not artificially supported.
• Precision further degrades fivefold with active or passive head movements.
• Monocular vision is unlikely to be degraded by natural gaze imprecision.
• Binocular vision discrepancies arise from vergence imprecision, challenging current models.

Conclusions:

• Head mobility substantially reduces gaze stability.
• Current psychophysical models of binocular vision may not fully account for natural conditions.
• Further research is needed to reconcile binocular vision performance with observed gaze imprecision.