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

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150338 ◽  
Author(s):  
Shelby E. Temple ◽  
Juliette E. McGregor ◽  
Camilla Miles ◽  
Laura Graham ◽  
Josie Miller ◽  
...  
Keyword(s):  
Light Field ◽  
Polarized Light ◽  
Age Related Macular Degeneration ◽  
Polarization Sensitivity ◽  
Polarization Angle ◽  
Self Assessment ◽  
Age Related ◽  
Polarization Of Light ◽  
Lower Limits

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.

scholarly journals Hyperspectral autofluorescence characterization of drusen and sub-RPE deposits in age-related macular degeneration

2021 ◽  
Vol 6 ◽  
pp. 4-4
Author(s):  
Yuehong Tong ◽  
Thomas Ach ◽  
Christine A. Curcio ◽  
R. Theodore Smith
Keyword(s):  
Macular Degeneration ◽  
Age Related Macular Degeneration ◽  
Age Related

scholarly journals An unsuccessful attempt to elicit orientation responses to linearly polarized light in hatchling loggerhead sea turtles ( Caretta caretta )

2011 ◽  
Vol 366 (1565) ◽  
pp. 757-762 ◽  
Author(s):  
Lydia M. Mäthger ◽  
Kenneth J. Lohmann ◽  
Colin J. Limpus ◽  
Kerstin A. Fritsches
Keyword(s):  
Light Field ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Sea Turtles ◽  
Polarized Light ◽  
Caretta Caretta ◽  
Polarization Sensitivity ◽  
Light Perception ◽  
Unsuccessful Attempt ◽  
Swimming Direction

Sea turtles undertake long migrations in the open ocean, during which they rely at least partly on magnetic cues for navigation. In principle, sensitivity to polarized light might be an additional sensory capability that aids navigation. Furthermore, polarization sensitivity has been linked to ultraviolet (UV) light perception which is present in sea turtles. Here, we tested the ability of hatchling loggerheads ( Caretta caretta ) to maintain a swimming direction in the presence of broad-spectrum polarized light. At the start of each trial, hatchling turtles, with their magnetic sense temporarily impaired by magnets, successfully established a steady course towards a light-emitting diode (LED) light source while the polarized light field was present. When the LED was removed, however, hatchlings failed to maintain a steady swimming direction, even though the polarized light field remained. Our results have failed to provide evidence for polarized light perception in young sea turtles and suggest that alternative cues guide the initial migration offshore.

scholarly journals Behavioural relevance of polarization sensitivity as a target detection mechanism in cephalopods and fishes

2011 ◽  
Vol 366 (1565) ◽  
pp. 734-741 ◽  
Author(s):  
Vincenzo Pignatelli ◽  
Shelby E. Temple ◽  
Tsyr-Huei Chiou ◽  
Nicholas W. Roberts ◽  
Shaun P. Collin ◽  
...  
Keyword(s):  
Target Detection ◽  
Polarized Light ◽  
Luminance Contrast ◽  
Polarization Sensitivity ◽  
Prey Detection ◽  
Free Swimming ◽  
Detection Mechanism ◽  
Set Up ◽  
Polarization Of Light

Aquatic habitats are rich in polarized patterns that could provide valuable information about the environment to an animal with a visual system sensitive to polarization of light. Both cephalopods and fishes have been shown to behaviourally respond to polarized light cues, suggesting that polarization sensitivity (PS) may play a role in improving target detection and/or navigation/orientation. However, while there is general agreement concerning the presence of PS in cephalopods and some fish species, its functional significance remains uncertain. Testing the role of PS in predator or prey detection seems an excellent paradigm with which to study the contribution of PS to the sensory assets of both groups, because such behaviours are critical to survival. We developed a novel experimental set-up to deliver computer-generated, controllable, polarized stimuli to free-swimming cephalopods and fishes with which we tested the behavioural relevance of PS using stimuli that evoke innate responses (such as an escape response from a looming stimulus and a pursuing behaviour of a small prey-like stimulus). We report consistent responses of cephalopods to looming stimuli presented in polarization and luminance contrast; however, none of the fishes tested responded to either the looming or the prey-like stimuli when presented in polarization contrast.

Polarization of Light in the Ocean

Ocean Optics ◽  
1994 ◽  
Author(s):  
George W. Kattawar
Keyword(s):  
Light Field ◽  
Polarized Light ◽  
Daily Routine ◽  
Selective Absorption ◽  
Mueller Matrices ◽  
Atmospheric Observations ◽  
History Of ◽  
The Many ◽  
Polarization Of Light ◽  
Solar Position

The effects of polarization on our perception of the environment about us have been recognized for at least 1000 years. The earliest reports were in response to the polarization in blue skylight as observed through various polarizing crystals. Since blue skylight is a source of polarized light, and atmospheric observations are a quite natural part of our daily routine, it is not surprising that an extraordinary amount of research on the polarization of skylight has been undertaken. Study of the polarization properties of the ocean and the hydrosols contained therein has, unfortunately been very limited, perhaps because man has not been a natural resident of the sea. This chapter will introduce a description of the polarized light field beneath the sea by first providing a brief history of polarization. This will familiarize the reader with its rather ubiquitous presence in our environment, even though our visual perception of it is very weak. Finally, a method is presented (Mueller matrices) to fully characterize the polarization properties of the submarine light field and the polarized effects that various hydrosols have on the light field. For a collection of the many diverse applications of polarization, the reader is referred to the excellent book by Gehrels (1974) About 1000 years ago, the Vikings discovered the dichroic properties of crystals such as cordierite. This property of exhibiting various colors when viewed from different directions is due to the selective absorption of waves oscillating along a particular plane of the crystal. When Vikings viewed the blue skylight through such crystals held in a certain orientation, they located portions of the sky relative to the solar position that seemed to disappear. With this discovery of the polarization of the blue sky, they learned to navigate even in the absence of the sun (e.g., when it was below the horizon). It was another six and one-half centuries before other polarization properties were reported (see Table 11-1 taken from Gehrels, 1974, and Können, 1985).

scholarly journals Effects of Mitochondrial-Derived Peptides (MDPs) on Mitochondrial and Cellular Health in AMD

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1102 ◽  
Author(s):  
Sonali Nashine ◽  
M. Cristina Kenney
Keyword(s):  
Mitochondrial Dysfunction ◽  
Macular Degeneration ◽  
Therapeutic Targets ◽  
Mechanisms Of Action ◽  
Age Related Macular Degeneration ◽  
Age Related

Substantive evidence demonstrates the contribution of mitochondrial dysfunction in the etiology and pathogenesis of Age-related Macular Degeneration (AMD). Recently, extensive characterization of Mitochondrial-Derived Peptides (MDPs) has revealed their cytoprotective role in several diseases, including AMD. Here we summarize the varied effects of MDPs on cellular and mitochondrial health, which establish the merit of MDPs as therapeutic targets for AMD. We argue that further research to delve into the mechanisms of action and delivery of MDPs may advance the field of AMD therapy.

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