Computer-Based Test to Quantify the Pulfrich Stereophenomenon

Publication

Computer-Based Test to Quantify the Pulfrich Stereophenomenon

Journal Paper/Review - Jul 3, 2009

Stadelmann Raphael, Jiang Xiaoyi, Mojon Daniel

Citation

Stadelmann R, Jiang X, Mojon D. Computer-Based Test to Quantify the Pulfrich Stereophenomenon. Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde 2009; 223:357-361.

Type

Journal Paper/Review (English)

Journal

Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde 2009; 223

Publication Date

Jul 3, 2009

Issn Electronic

1423-0267

Pages

357-361

Brief description/objective

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.