Eyes

White blood cells

March 11

If you had said that it’s possible to see white blood cells with the naked eye, I wouldn’t have believed you. If you had somehow convinced me, I’d have then been impressed. But never would I have thought that it’s possible to see your own white blood cells in your own eye. Aye, ’tis true!

The blue field entoptic phenomenon is an entoptic phenomenon characterized by the appearance of tiny bright dots (nicknamed blue-sky sprites) moving quickly along undulating pathways in the visual field, especially when looking into bright blue light such as the sky.

~ Wikipedia from, https://en.wikipedia.org/wiki/Blue_field_entoptic_phenomenon

Is the takeaway here that you’ve just learned something? …or that wonders never cease? …or something else entirely?

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The yellow bow tie in your eye

March 3, 2023

I mean it took 10 minutes sitting in a cafe staring at my laptop screen and repeatedly cocking my head back and forth, like an absolute goon, but I can see Haidinger’s brushes!

~ Matt Webb from, https://interconnected.org/home/2022/07/27/filtered

If you like what I’m doing, you’ll probably also like Webb’s Interconnected. I was skimming through, and spun off digging into optics and eyes and yellow bow ties. I’ve never (or I’ve completely forgotten) known about this before today. Like Webb, I was astounded to realize that I can see Haidinger’s brushes. It’s an optical phenomenon in the macula of the retina. Not everyone has the biology to see it, but with certain light coming into your eye this defect of our magnificent optical systems is revealed. Just when I think, “meh, what wonders could possibly be left…”

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Forget glowing noses

January 16, 2023

During the summer, when the sun spends months above the horizon, the inner parts of the animals’ eyes, a structure called the tapetum lucidum, gleam a shimmering gold. But as the landscape dips into the perpetual darkness of winter, their eyes turn a rich blue.

~ Katherine J. Wu from, https://www.theatlantic.com/science/archive/2022/06/reindeer-eyes-winter-vision-adaptation/661419/

Forget glowing noses; reindeer eyes are magic. This is a short, punchy, pop-sci article— and is exactly the sort of random, interesting thing I delight in trawling through RSS feeds to locate.

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