The Influence of Target Angular Velocity on Visual Latency Difference Determined using the Rotating Pulfrich Effect

Abstract

Visual latency difference was determined directly in normal volunteers, using the rotating Pulfrich technique described by Nickalls [Vision Research, 26, 367-372 (1986)]. Subjects fixated a black vertical rod rotating clockwise on a horizontal turntable turning with constant angular velocity (16.6,33.3 or 44.7 revs/min) with a neutral density filter (OD 0.7 or 1.5) in front of the right eye. For all subjects the latency difference associated with the 1.5 OD filter was significantly greater (P < 0.001) with the rod rotating at 16.6 rev/min than at 33.3 revs/min. The existence of an inverse relationship between latency difference and angular velocity is hypothesized.

Effect of Speed Overestimation on Flash-Lag Effect at Low Luminance

“…Consistent with these results, Nickalls (1996) has shown a decrease in Pulfrich effect at faster angular velocities with a rotating stimulus.…”

A conic theorem generalised: directed angles and applications

“…This theorem crystallised from some experimental observations [4,5] in the area of vision physiology-a rich source of interesting mathematical problems. Hopefully, this article gives a flavour of the power of directed angles and brings to life a curious theorem, which can be used to establish tangent-focus properties of conics via an unusual perspective.…”

The Pulfrich Phenomenon: Practical Implications of the Assessment of Cases and Effectiveness of Treatment

“…19 The most commonly documented influence on the effect of the Pulfrich phenomenon is the velocity of the stimulus. 7,8 It is reasonable to assume that many of the patients seen may have had true symptoms which were not demonstrated during the Pulfrich assessment as the pendulum did not move at a great enough speed to elicit their symptoms. The velocity of the pendulum was unfortunately not something that could be measured or controlled in the clinic and it is therefore possible that those with milder symptoms were not detected.…”

“…1,5,6 The magnitude of the displacement has been shown to increase as object velocity is increased. 7,8 As the pendulum motion is fastest at the centre of the swing, the apparent displacement will therefore be greatest at this point. The displacement is zero when the pendulum pauses momentarily before switching direction, which results in the perception of an elliptical path followed by the object.…”