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Abstract
Individual psychological responses to heights vary on a continuum from acrophobia
to height intolerance, height tolerance, and height enjoyment. This paper reviews
the English literature and summarizes the physiologic and psychological factors that
generate different responses to heights while standing still in a static or motionless
environment. Perceptual cues to height arise from vision. Normal postural sway of
2 cm for peripheral objects within 3 m increases as eye-object distance increases.
Postural sway >10 cm can result in a fall. A minimum of 20 minutes of peripheral retinal
arc is required to detect motion. Trigonometry dictates that a 20-minute peripheral
retinal arch can no longer be achieved in a standing position at an eye-object distance
of >20 m. At this distance, visual cues conflict with somatosensory and vestibular
inputs, resulting in variable degrees of imbalance. Co-occurring deficits in the visual,
vestibular, and somatosensory systems can significantly increase height imbalance.
An individual's psychological makeup, influenced by learned and genetic factors, can
influence reactions to height imbalance. Enhancing peripheral vision and vestibular,
proprioceptive, and haptic functions may improve height imbalance. Psychotherapy may
improve the troubling subjective sensations to heights.