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visual angle

noun
  1. the angle subtended by an object at the lens of the eye
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
visual angle in Medicine

visual angle

n.
  1. The angle formed at the retina by the meeting of lines drawn from the periphery of the viewed object.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.