Polarized Light and You

“A Party for Your Eyes”

Humans perceive polarized light. This is little known, but true.

After reading about this, I decided to try a pair of polarized sunglasses – which I had never bothered to try before. These particular glasses are amber, which I think   is an important aspect of the effects I noticed. They were not particularly fancy and about $25 Canadian at a local pharmacy. (That would be under $20 US.)

Basically, these glasses are “a party for your eyes”. This effect occurs when walking about and looking at flowers and greenery during daylight – particularly if the sun is shining on the trees and plants that you are looking at. It is now highly motivating to put these glasses on and take my eyes out and about for a walk during daylight hours and just enjoy how stunningly beautiful the vegetation and sky looks. I wish I could take photos to show and keep-sake what it all looks like.

Mostly, our exposure to polarized light has been sunlight. Now, we spend a lot of time exposed to light from electronic screens. The light from LED screens contains 100% polarized light. The effects of this have not received much attention, but since polarized light historically meant daylight to us, it seems reasonable to wonder if polarized light might be “activating” in the same way blue light waves are.

From July, 2015, here is a report on the science of human perception of polarized light.  LINK  Please see the article to understand the quote below better.

“This result shows that your cornea can dramatically affect how you perceive polarized light,” said Dr McGregor. As the optical properties of the cornea vary between individuals, this may partly explain why people often report their experience of seeing Haidinger’s brushes quite differently.

Dr Temple explains: “You can see Haidinger’s brushes if you look at a blank white portion of an LCD screen on a computer, tablet or phone. Tilt your head from side to side and faint yellow brushes should become visible. With practice, you can then see them in the blue parts of the sky at 90 degrees from the sun.”

The ability to see Haidinger’s brushes is associated with the organisation of carotenoid pigments in the macula (a pigmented area that covers and protects the central part of the retina). The risk of acquiring Age-related Macular Degeneration (AMD) has previously been correlated with low carotenoid pigment density in the macula. The researchers are presently adapting their approach with the aim of developing a screening device to detect individuals at high risk of AMD, currently the leading cause of blindness in the developed world.

Certain molecules, from food, called “carotenoids” are involved.

Carotenoids are found in the diet in things like egg yolks and leafy greens. Carotenoids have been studied for years because they are also involved in protecting the eyes from the damaging energy in the blue and ultra-violet light rays we are exposed to. Carotenoids are fat-soluble, and so are much more absorbed from foods like salad greens when fat is eaten at the same meal.

Here is an article that details the dietary sources of the important eye pigments lutein and zeaxanthin here LINK.  “Dietary Sources of Lutein and Zeaxanthin Carotenoids and Their Role in Eye Health” This article reviews the potential roles of these molecules in eye health, particularly in regards to cataracts and age-related macular degeneration.

“Lutein and zeaxanthin are the most common xanthophylls in green leafy vegetables (e.g., kale, spinach, broccoli, peas and lettuce) and egg yolks [25] (Table 1).”

“Chicken egg yolk is deemed a better source of lutein and zeaxanthin compared to fruits and vegetables because of its increased bioavailability due to the high fat content in eggs [31,32]. The concentrations of lutein and zeaxanthin in chicken egg yolk are 292 ± 117 µg/yolk and 213 ± 85 µg/yolk (average weight of yolk is about 17–19 g), respectively and are likely dependent on the type of feed, found mainly in on-esterified form with minute amounts of lycopene and β-carotene [33].”

 

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