Haidinger’s brushes elicited at varying degrees of polarization rapidly and easily assesses total macular pigmentation

Abstract

Macular pigments (MPs), by absorbing potentially toxic short-wavelength (400-500 nm) visible light, provide protection against photo-chemical damage thought to be relevant in the pathogenesis of age-related macular degeneration (AMD). A method of screening for low levels of MPs could be part of a prevention strategy for helping people to delay the onset of AMD. We introduce a new method for assessing MP density that takes advantage of the polarization-dependent absorption of blue light by MPs, which results in the entoptic phenomenon called Haidinger's brushes (HB). Subjects were asked to identify the direction of rotation of HB when presented with a circular stimulus illuminated with an even intensity of polarized white light in which the electric field vector was rotating either clockwise or anticlockwise. By reducing the degree of polarization of the stimulus light, a threshold for perceiving HB (degree of polarization threshold) was determined and correlated (r 2 0.66) to macular pigment optical density assessed using dual-wavelength fundus autofluoresence. The speed and ease of measurement of degree of polarization threshold makes it well suited for large-scale screening of macular pigmentation.

Polarization perception in humans: on the origin of and relationship between Maxwell’s spot and Haidinger’s brushes

“…The macular dependence and interrelationship between HB, MS and pMS established in this study suggest that they can all be used as tests of macular function in health and disease. Such tests are well documented for HB [20][21][22]25,26 , but the clinical utility of MS and pMS deserves further investigation, particularly with respect to the diagnosis/assessment of macular disease such as age-related macular degeneration and diabetic maculopathy.…”

“…This is important because of the possible clinical application of these phenomena in the diagnosis and monitoring of various eye and vision-related disorders [20][21][22] , including amblyopia 23 , dyslexia 24 and age-related macular degeneration 25 . Quantification of HB perception has recently been proposed as a rapid and easy method for assessing macular pigment density in otherwise healthy individuals as part of health screening and blue-light hazard avoidance 26 . Advancing our understanding of these phenomena, in terms of both their generation and relationship, is essential for their full utilisation as diagnostic and investigative ophthalmic tools.…”

The Effect of Age-Related Macular Degeneration on Polarization Pattern Perception

“…Sensitivity measures of polarization-modulated stimuli have the potential to provide a highly targeted means by which to assess macular function in health and disease, 1 , 3 , 11 , 13 , 18 a fact that has been recognized for some time. 9 , 12 Currently, however, such measures are rarely if ever used in daily clinical practice.…”

The electrophysiological response to polarization-modulated patterned visual stimuli

“…It is also worth noting that our polarization responses reflect a pure macular response, and as such there was no contribution to the responses from peripheral retina, a state which is unlikely with conventional VEP recordings. It is known that the latency of conventional VEP responses varies with the extent to which the magnocellular pathway contributes to the evoked potential, with greater involvement leading to shorter latencies (Baseler and Sutter, 1997) Clinical applications of polarization sensitivity, either to Haidinger's Brushes or to the more quantifiable polarization pattern perception, have been discussed elsewhere with respect to the diagnosis and monitoring of macular disease (Muller et al, 2016;Misson & Anderson, 2017), and the measurement of macular pigment density (Temple et al, 2019). Our findings that polarization stimuli also generate recordable visual evoked cortical responses extend the clinical application of human polarization perception to an objective test of macular function that does not rely on a conscious response.…”

“…The foveal origin of both phenomena implies that any electrophysiological response to a polarization stimulus is specifically dependent on the structural and functional integrity of the fovea and foveal visual pathways. This specificity led to propositions that Haidinger's brushes and PPP might be clinically useful, particularly with respect to the early diagnosis and management of age-related macular degeneration (Goldschmidt, 1950;Muller, Muller, Gliem, Kupper, Holz, Harmening & Charbel Issa, 2016;Stanworth & Naylor, 1955;Temple, Roberts & Misson, 2019).…”