Encyclopedia of Clinical Neuropsychology

2018 Edition
| Editors: Jeffrey S. Kreutzer, John DeLuca, Bruce Caplan

Visual Angle

  • Joan SwearerEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-3-319-57111-9_1411

Synonyms

Visual subtense

Definition

Visual angle is a dimension used to indicate the size of visual stimuli subtended at the eye without having to specify actual stimulus size or distance and is used to specify intraocular dimensions.

Current Knowledge

Visual angle predicts the amount of space that an image will subtend on the retina and describes the relative location of separate retinal images. It is also used to specify the size of spatial frequency gratings. It is formed by incoming light rays at the nodal point of the eye and is dependent on the size of the stimulus, its distance from the observer, and whether or not it is viewed in the frontal plane. In a simplified model, visual angle is formed from the light rays from two points (in height, width, or depth) of a viewed object as they enter the eye and is proportional to the angle projected onto the retina. The size of the subtended image is thus determined by the visual angle. An object viewed from different distances will have...

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References and Readings

  1. De Valois, R. L., & De Valois, K. K. (1988). Spatial vision. New York: Oxford University Press.Google Scholar
  2. O’Shea, R. P. (1991). Thumb’s rule tested: Visual angle of the thumb’s width is about 2 deg. Perception, 20, 415–418.PubMedCrossRefPubMedCentralGoogle Scholar
  3. Scharff, L. V. (2003). Sensation and perception research methods. In S. F. Davis (Ed.), Handbook of research methods in experimental psychology (pp. 263–284). Malden: Blackwell.CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of NeurologyUniversity of Massachusetts Medical SchoolWorcesterUSA