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Perceiving polarization with the naked eye: characterization of human polarization sensitivity

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journal contribution
posted on 18.02.2016, 10:21 by Juliette Elizabeth McGregor, S. E. Temple, C. Miles, L. Graham, J. Miller, J. Buck, N. E. Scott-Samuel, N. W. Roberts
Like many animals, humans are sensitive to the polarization of light. We can detect the angle of polarization using an entoptic phenomenon called Haidinger's brushes, which is mediated by dichroic carotenoids in the macula lutea. While previous studies have characterized the spectral sensitivity of Haidinger's brushes, other aspects remain unexplored. We developed a novel methodology for presenting gratings in polarization-only contrast at varying degrees of polarization in order to measure the lower limits of human polarized light detection. Participants were, on average, able to perform the task down to a threshold of 56%, with some able to go as low as 23%. This makes humans the most sensitive vertebrate tested to date. Additionally, we quantified a nonlinear relationship between presented and perceived polarization angle when an observer is presented with a rotatable polarized light field. This result confirms a previous theoretical prediction of how uniaxial corneal birefringence impacts the perception of Haidinger's brushes. The rotational dynamics of Haidinger's brushes were then used to calculate corneal retardance. We suggest that psychophysical experiments, based upon the perception of polarized light, are amenable to the production of affordable technologies for self-assessment and longitudinal monitoring of visual dysfunctions such as age-related macular degeneration.

History

Citation

Proceedings of the Royal Society B: Biological Sciences, 2015, 282(1811), 20150338

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/MBSP Non-Medical Departments/Neuroscience, Psychology and Behaviour

Version

VoR (Version of Record)

Published in

Proceedings of the Royal Society B: Biological Sciences

issn

0962-8452

eissn

1471-2954

Acceptance date

28/05/2015

Copyright date

2015

Available date

18/02/2016

Publisher version

http://rspb.royalsocietypublishing.org/content/282/1811/20150338

Language

en