BACKGROUND: Many eye and brain diseases may induce a spontaneous Pulfrich phenomenon (PP), a stereoillusion leading to misjudgments of objects moving in a frontoparallel plane. Since, until now, no simple PP quantification method has been available, a computer pendulum (CP) system was developed and evaluated. METHODS: In 5 normal subjects, PP was induced with different neutral density filters. The resulting retardations were measured with the gold standard (a mechanical pendulum; MP), and compared to a CP, allowing the generation of interocular image phase shifts. RESULTS: A high correlation between MP and CP was found (r = 0.97, p < 0.001; slope 0.91, p > 0.1 for difference with slope 1.0). A multiple linear regression showed a significant influence of the filter density and the subject tested. The type of pendulum (MP or CP) and the side on which the filter was held were nonsignificant. CONCLUSIONS: A CP allowing an interocular image phase shift can be used as an alternative to a MP for quantification of a PP. Thus, this principle would allow the development of software or an Internet-based test for PP quantification. However, in some subjects, the CP will overestimate and in others underestimate the real retardation measured with the MP. Copyright 2009 S. Karger AG, Basel.
BACKGROUND: Many eye and brain diseases may induce a spontaneous Pulfrich phenomenon (PP), a stereoillusion leading to misjudgments of objects moving in a frontoparallel plane. Since, until now, no simple PP quantification method has been available, a computer pendulum (CP) system was developed and evaluated. METHODS: In 5 normal subjects, PP was induced with different neutral density filters. The resulting retardations were measured with the gold standard (a mechanical pendulum; MP), and compared to a CP, allowing the generation of interocular image phase shifts. RESULTS: A high correlation between MP and CP was found (r = 0.97, p < 0.001; slope 0.91, p > 0.1 for difference with slope 1.0). A multiple linear regression showed a significant influence of the filter density and the subject tested. The type of pendulum (MP or CP) and the side on which the filter was held were nonsignificant. CONCLUSIONS: A CP allowing an interocular image phase shift can be used as an alternative to a MP for quantification of a PP. Thus, this principle would allow the development of software or an Internet-based test for PP quantification. However, in some subjects, the CP will overestimate and in others underestimate the real retardation measured with the MP. Copyright 2009 S. Karger AG, Basel.
Authors: C Vijay Reena Durai; Siddhart Rajendran; Michael A Webster; Sandeep Vempati; Shrikant R Bharadwaj Journal: Vision Res Date: 2021-07-05 Impact factor: 1.984