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What Causes Eye Floaters?

Eye image via Shutterstock

Eye floaters — or muscae volitantes, Latin for “hovering flies" — are those tiny, oddly shaped objects that sometimes appear in your vision, most often when you’re looking at the sky on a sunny day. They look like spots, or a squishy little amoeba, and drift aimlessly around in your field of vision. Try to get a fix on one, though, and it seems to disappear.

Floaters aren’t just optical illusions. You’re really seeing them, and they’re actually in your eye, not just on it or in front of it. The weird little squiggles are pieces of the vitreous humor, the fluid that fills the eye, breaking off and then floating about in your eyeball.

A little gross, I know, but completely normal. The vitreous humor fills the gap between your retina and lens and helps maintain the round shape of your eye. It’s made up of water bound up in a little hyaluronic acid and collagen. When you’re young, it’s thick and gel-like, but as you age, the hyaluronic acid network breaks down and releases the trapped water molecules. As this happens, the core of the vitreous humor becomes more watery and little bits of undissolved gel break off and slowly drift around. When light passes through the eye, the shadows of these pieces are thrown up on your retina and you perceive them as floaters.

A Closer Look

Since floaters, well, float, their paths generally follow the motion of the eye. This makes looking right at them difficult, and when you shift your gaze towards them, they often move and stay at the edges. They don’t always float, though, and many of them will sink towards the bottom of the eyeball. To get a good look at them, just lie down looking up at a clear sky. Some of the floaters will settle near the fovea, a small area that sits at the back center of your eye and is responsible for your sharp central vision. The lack of movement and the even, textureless background makes it easy to scope them out and watch the blobs bob around a little.

For the most part, floaters are nothing to worry about — just a sign that you’re not a kid anymore. The sudden appearance of a lot of floaters combined with the onset of other eye weirdness — like flashes of light or blurriness or loss of peripheral vision — could indicate a problem, though. Sometimes, floaters are a symptom of the vitreous humor pulling away from the retina, a retinal tear, or the abnormal growth of blood vessels in the eye. If your floaters cross the line from curiosity to nuisance, it’s time to give the eye doctor a call.

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Big Questions
Why Does the Queen Have Two Birthdays?
CHRIS JACKSON, AFP/Getty Images
CHRIS JACKSON, AFP/Getty Images

On April 21, Her Majesty Queen Elizabeth II will turn 92 years old. To mark the occasion, there are usually a series of gun salutes around London: a 41 gun salute in Hyde Park, a 21 gun salute in Windsor Great Park, and a 62 gun salute at the Tower of London. For the most part, the monarch celebrates her big day privately. But on June 9, 2018, Her Majesty will parade through London as part of an opulent birthday celebration known as Trooping the Colour.

Queen Elizabeth, like many British monarchs before her, has two birthdays: the actual anniversary of the day she was born, and a separate day that is labeled her "official" birthday (usually the second Saturday in June). Why? Because April 21 is usually too cold for a proper parade.

The tradition started in 1748, with King George II, who had the misfortune of being born in chilly November. Rather than have his subjects risk catching colds, he combined his birthday celebration with the Trooping the Colour.

The parade itself had been part of British culture for almost a century by that time. At first it was strictly a military event, at which regiments displayed their flags—or "colours"—so that soldiers could familiarize themselves. But George was known as a formidable general after having led troops at the Battle of Dettingen in 1743, so the military celebration seemed a fitting occasion onto which to graft his warm-weather birthday. Edward VII, who also had a November birthday, was the first to standardize the June Trooping the Colour and launched a tradition of a monarchical review of the troops that drew crowds of onlookers.

Even now, the date of the "official" birthday varies year to year. For the first seven years of her reign, Elizabeth II held her official birthday on a Thursday but has since switched over to Saturdays. And while the date is tied to the Trooping the Colour in the UK, Commonwealth nations around the world have their own criteria, which generally involve recognizing it as a public holiday.

Australia started recognizing an official birthday back in 1788, and all the provinces (save one) observe the Queen's Birthday on the second Monday in June, with Western Australia holding its celebrations on the last Monday of September or the first Monday of October.

In Canada, the official birthday has been set to align with the actual birth date of Queen Victoria—May 24, 1819—since 1845, and as such they celebrate so-called Victoria Day on May 24 or the Monday before.

In New Zealand, it's the first Monday in June, and in the Falkland Islands the actual day of the Queen's birth is celebrated publicly.

All in all, just another reason it's great to be Queen.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Big Questions
What Is the Meaning Behind "420"?
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Whether or not you’re a marijuana enthusiast, you’re probably aware that today is an unofficial holiday for those who are. April 20—4/20—is a day when pot smokers around the world come together to, well, smoke pot. Others use the day to push for legalization, holding marches and rallies.

But why the code 420? There are a lot of theories as to why that particular number was chosen, but most of them are wrong. You may have heard that 420 is police code for possession, or maybe it’s the penal code for marijuana use. Both are false. There is a California Senate Bill 420 that refers to the use of medical marijuana, but the bill was named for the code, not the other way around.

As far as anyone can tell, the phrase started with a bunch of high school students. Back in 1971, a group of kids at San Rafael High School in San Rafael, California, got in the habit of meeting at 4:20 to smoke after school. When they’d see each other in the hallways during the day, their shorthand was “420 Louis,” meaning, “Let’s meet at the Louis Pasteur statue at 4:20 to smoke.”

Somehow, the phrase caught on—and when the Grateful Dead eventually picked it up, "420" spread through the greater community like wildfire. What began as a silly code passed between classes is now a worldwide event for smokers and legalization activists everywhere—not a bad accomplishment for a bunch of high school stoners.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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