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Updated: Jun 19, 2026

Motion-Acuity Test for Visual Field Acuity Measurement with Motion-Defined Shapes
Published on: February 23, 2024
AREA AND VISUAL THRESHOLD
1Laboratory of Biophysics of Columbia University, New York, and The Biological Laboratories, Harvard University, Cambridge.
Abstract:
1. The variation of threshold with field area was measured in fields homogeneous in rod-cone composition. At 15 degrees above the fovea, an increase in field diameter from 1 degrees to 5 degrees reduces the threshold sevenfold, at 25 degrees above the fovea tenfold. 2. These changes are shown to follow qualitatively from simple statistical properties of the retinal mosaic. Analytic treatment leads to the expression, (A - n(t))(k) I = C, in which A = area, n(t) = constant threshold number of elements, I = threshold intensity, and k and C are constants. This equation describes the available data accurately, and is the general form of previous empirical area-threshold formulae.
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