scholarly journals A contrast-based Pulfrich effect in normals and a spontaneous Pulfrich effect in amblyopes

2017 ◽  
Vol 17 (10) ◽  
pp. 155
Author(s):  
Alexandre Reynaud ◽  
Robert Hess
Keyword(s):  
Pulfrich Effect

Pulfrich Effect for Vision Therapy

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Pellumb  Kllogjeri
Keyword(s):  
Pulfrich Effect ◽  
Vision Therapy

scholarly journals The stroboscopic Pulfrich effect is not evidence for the joint encoding of motion and depth

10.1167/5.5.3 ◽  
2005 ◽  
Vol 5 (5) ◽  
pp. 3 ◽  
Author(s):  
Jenny C. A. Read ◽  
Bruce G. Cumming
Keyword(s):  
Pulfrich Effect ◽  
Joint Encoding

scholarly journals Effect of Interocular Delay on Disparity-Selective V1 Neurons: Relationship to Stereoacuity and the Pulfrich Effect

2005 ◽  
Vol 94 (2) ◽  
pp. 1541-1553 ◽  
Author(s):  
Jenny C. A. Read ◽  
Bruce G. Cumming
Keyword(s):  
Stereo Matching ◽  
Striate Cortex ◽  
Temporal Integration ◽  
Gaussian Function ◽  
Great Majority ◽  
Integration Time ◽  
V1 Neurons ◽  
Temporal Properties ◽  
Pulfrich Effect ◽  
Behaving Monkeys

The temporal properties of disparity-sensitive neurons place important temporal constraints on stereo matching. We examined these constraints by measuring the responses of disparity-selective neurons in striate cortex of awake behaving monkeys to random-dot stereograms that contained interocular delays. Disparity selectivity was gradually abolished by increasing interocular delay (when the delay exceeds the integration time, the inputs from the 2 eyes become uncorrelated). The amplitude of the disparity-selective response was a Gaussian function of interocular delay, with a mean of 16 ms (±5 ms, SD). Psychophysical measures of stereoacuity, in both monkey and human observers, showed a closely similar dependency on time, suggesting that temporal integration in V1 neurons is what determines psychophysical matching constraints over time. There was a slight but consistent asymmetry in the neuronal responses, as if the optimum stimulus is one in which the right stimulus leads by about 4 ms. Because all recordings were made in the left hemisphere, this probably reflects nasotemporal differences in conduction times; psychophysical data are compatible with this interpretation. In only a few neurons (5/72), interocular delay caused a change in the preferred disparity. Such tilted disparity/delay profiles have been invoked previously to explain depth perception in the stroboscopic version of the Pulfrich effect (and other variants). However, the great majority of the neurons did not show tilted disparity/delay profiles. This suggests that either the activity of these neurons is ignored when viewing Pulfrich stimuli, or that current theories relating neuronal properties to perception in the Pulfrich effect need to be reevaluated.

scholarly journals Contact lenses, the reverse Pulfrich effect, and anti-Pulfrich monovision corrections

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Victor Rodriguez-Lopez ◽  
Carlos Dorronsoro ◽  
Johannes Burge
Keyword(s):  
Processing Speed ◽  
Moving Objects ◽  
Contact Lenses ◽  
Three Dimensional ◽  
Effect Sizes ◽  
Reported Effect ◽  
Pulfrich Effect ◽  
Image Blur ◽  
Optical Blur ◽  
Large Magnification

Abstract Interocular differences in image blur can cause processing speed differences that lead to dramatic misperceptions of the distance and three-dimensional direction of moving objects. This recently discovered illusion—the reverse Pulfrich effect—is caused by optical conditions induced by monovision, a common correction for presbyopia. Fortunately, anti-Pulfrich monovision corrections, which darken the blurring lens, can eliminate the illusion for many viewing conditions. However, the reverse Pulfrich effect and the efficacy of anti-Pulfrich corrections have been demonstrated only with trial lenses. This situation should be addressed, for clinical and scientific reasons. First, it is important to replicate these effects with contact lenses, the most common method for delivering monovision. Second, trial lenses of different powers, unlike contacts, can cause large magnification differences between the eyes. To confidently attribute the reverse Pulfrich effect to interocular optical blur differences, and to ensure that previously reported effect sizes are reliable, one must control for magnification. Here, in a within-observer study with five separate experiments, we demonstrate that (1) contact lenses and trial lenses induce indistinguishable reverse Pulfrich effects, (2) anti-Pulfrich corrections are equally effective when induced by contact and trial lenses, and (3) magnification differences do not cause or impact the Pulfrich effect.

Influence of Peripheral on Central Stereopsis: An Induced Depth Tilt Effect

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 276-276
Author(s):  
S Müller ◽  
E R Wist
Keyword(s):  
Opposite Direction ◽  
Rotation Speed ◽  
Neutral Density ◽  
Neutral Density Filter ◽  
Disk Rotation ◽  
Optimal Rotation ◽  
Density Filter ◽  
Pulfrich Effect ◽  
Variable Errors ◽  
Tilted Disk

A large rotating black/white sectored disk (58 deg diameter) viewed with a neutral density filter over one eye is perceived as tilted in depth according to the Pulfrich phenomenon. But with fixation on a centrally located vertical bar (7 deg in length), the disk is perceived as vertical while the central bar is perceived as tilted in the opposite direction. This effect remains even if the central 38 deg portion of the disk is occluded leaving a peripheral annulus 10 deg in width. At an optimal rotation speed of 45° s−1 and a filter of 2 log units, the inter-individual perceived tilt of the bar ranges between 5° and 10° as measured by nulling out the illusory tilt by adjustment with a joystick. Variable errors were extremely small and corresponded well with central stereoscopic resolution. The amount of illusory tilt depends on the speed of disk rotation and filter density, and its direction on the relation between the direction of motion and the filter-covered eye. The effect is not limited to Pulfrich-induced stereotilt: When the disk was stationary but physically tilted in depth, the induced tilt on the central bar corresponded to about 50% of the physical tilt. This effect, in turn, could be cancelled or enhanced by rotating the tilted disk and inducing an appropriate Pulfrich effect. With monocular viewing no induced depth tilt occurs. The results are interpreted in terms of a stereoscopic induced effect operating beyond the known peripheral limits of stereopsis.

Some aspects of the Pulfrich effect

1973 ◽  
Vol 14 (1) ◽  
pp. 87-90 ◽  
Author(s):  
STURLA KREKLING
Keyword(s):  
Pulfrich Effect

Pulfrich effect with minimal differential adaptation of the eyes

1968 ◽  
Vol 8 (11) ◽  
pp. 1431-1443 ◽  
Author(s):  
P.C. Dodwell ◽  
G.S. Harker ◽  
I. Behar
Keyword(s):  
Differential Adaptation ◽  
Pulfrich Effect
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