Computer-Based Test to Quantify the Pulfrich Stereophenomenon

• Published in: Ophthalmologica (Basel) Vol. 223; no. 6; pp. 357 - 361
• Main Authors: Stadelmann, Raphael, Jiang, Xiaoyi, Mojon, Daniel S.
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.01.2009; S. Karger AG
• Subjects: Adult; Biological and medical sciences; Depth Perception; Diagnosis, Computer-Assisted; Diagnostic Techniques, Ophthalmological - instrumentation; Female; Humans; Linear Models; Male; Medical sciences; Middle Aged; Miscellaneous; Motion Perception; New Technologies in Ophthalmology; Ophthalmology; Optical Illusions; Perceptual Disorders - diagnosis; Software; Young Adult; Diagnostic techniques; Depth perception; Optic neuropathy; Binocular vision; Stereopsis; Spatial vision; Neuro-ophthalmology; Motion perception; Motion; Depth; Computer; Perception; Diagnosis; Ophthalmology; Technique
• ISSN: 0030-3755; 1423-0267
• DOI: 10.1159/000227132

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.