What Exactly are Eye Floaters?

“I’ll look over there!”

“I’ll move over HERE!”

“You got an answer for everything.”

So.  Have you ever been looking at a book, the sky, or anything really, and seen what most people call “eye floaters?”  You know, the really weird almost chromosome-looking things that seem to just effortlessly and painlessly dance across our vision whenever the hell they want?  Like so:

These little buggers are the product of eye aging and the disintegration of the goo inside the eyeball itself.  If you’ve ever spent any time at all staring at eye floaters, you know that they can be fairly entertaining!

Inside of the eye ball, there is a liquid that gives the eye its shape and acts as a light medium (consequently with a Refractive Index of 1.336) to get light to the retina.  This liquid isn’t quite a liquid and isn’t quite a gel, but the consistency of it is sort of like that of Jell-O.  it’s called the Vitreous Humor, or the Vitreous body, or simply just the Vitreous.  This stuff is pretty neat, as it’s completely transparent as we’re born through teen-hood.  The vitreous is made of about 99% water, along with some sugars, some salts, some collagen fibers, and these pretty cool cells called phagocytes.  The phagocytes’ main purpose is to hunt down and kill foreign bodies in the eye’s vitreous body and visual field.  Pretty cool, eh?

The vitreous body is a stagnant body of fluid; it does not have a regeneration process either, which means if you sustain some damage to an eye or both, they’re gone, as once the vitreous is gone, it is gone forever.  This is a great reason to ALWAYS wear safety goggles and eye protection whenever you’re doing something that could impact the eye ball.  I had a pretty scary experience one summer when I was still in undergraduate study, away on an opera tour.  I was building the set we were touring, and a piece of a table saw blade sheared away and shot itself right into my eyeball.  I spent several hours at the hospital as the doc tried to grab that piece of metal and dislodge it from my eyeball, about 3 millimeters from the edge of my pupil.  I got lucky.  I did have safety glasses on, too – which goes to show you that you can never be too careful.  After the ER doc dug that piece of blade out of my eye, they inserted a plastic lens attached to a bag of saline that drained around my eyeball to clean out any extra debris.  The resulting pic was pretty hilarious, and I was in good spirits, making jokes.  Ann Davis, thingmaker extraordinaire, took the photo, circa 1998:

As we get older, parts of the Vitreous degenerate and clump, creating the little eye floaters we’re so fond of seeing.  These things remain in the eye for as long as we are old, until we either A) die, or B) have them surgically removed.  For most people these things aren’t a problem at all, we just deal with them.  For some, however, they become so numerous and so vision-impairing that surgery IS required for removal of all of the clumped bits of whatever matter the eye floaters are made from — old proteins, bits of clumped collagen cell bundles, foreign bodies, retinal cells, etcetera.

Eye floaters do have some different types — from Wikipedia’s entry on floaters:

The common type of floater, which is present in most people’s eyes, is due to degenerative changes of the vitreous humour. The perception of floaters is known as myodesopsia, or less commonly as myiodeopsia, myiodesopsia, or myodeopsia.  They are also called Muscae volitantes (from the Latin, meaning “flying flies”), or mouches volantes (from the French). Floaters are visible because of the shadows they cast on the retina or their refraction of the light that passes through them, and can appear alone or together with several others in one’s field of vision. They may appear as spots, threads, or fragments of cobwebs, which float slowly before the observer’s eyes.  Since these objects exist within the eye itself, they are not optical illusions but are entoptic phenomena.

What I find cool about eye floaters is that you’re actually seeing the shadow of the floaters on your retina, like a Linnebach projector.  Remember those?  As the light passes through the iris, it blows through the vitreous body and the floaters get in the way, causing shadows on the retina that your brain decodes as the floaters’ shape and size.

Now let me say this — most times, eye floaters are harmless bits of entertainment that all people have in some form or another.  However, sometimes eye floaters can be indications of a larger problem, like eye disease brought around by diabetes, carotid artery disease, or even as an indicator of a stroke or heart attack that may be imminent.  Sometimes eye floaters might be accompanied by flashes of light; this is a certain time to hit the doctor’s office.  A lesser known ailment, one that keeps on giving, per se, is ocular herpes.  As scary as that sounds, it is!  The vitreous can also become detached, too — as you age, the vitreous body sort of liquefies and detaches from the retina, which also causes eye floaters.  I’m certainly not a doctor, and you should use your own judgement when it comes to your health.  But if you have lots and lots and lots of floaters, perhaps it’s time to visit your doc.

A detailed article about determining when your eye floaters might indicate a larger problem is here – check it out.

Some fun facts on eye floaters, from Today I Found Out:

• Interestingly, if the eye floaters would just stay still instead of floating around, your brain would automatically tune them out and you’d never consciously see them.  Your brain does this all the time with things both in and outside of your eyes.  One example of this inside your eye are blood vessels in the eye which obstruct light; because they are fixed in location, relative to the retina, your brain tunes them out completely and you don’t consciously perceive them.
• The reason you can see floaters better when looking at, for instance, a bright blue sky, is because your pupils contract to a very small size, thus reducing the aperture, which in turn makes floaters more apparent and focused.
• Individual floaters often won’t change much throughout your lifetime, typically retaining their basic shape and size.
• The perception of eye floaters is known as myodesopsia.
• The reason the floating specs never seem to stay still is because floaters, being suspended in the vitreous humor,  move when your eye moves.  So as you try to look at them, they will appear to drift with your eye movement.
• Eye floaters are examples of entoptic phenomena.  Entoptic phenomena are things we see where the source is within the eye itself.
• If you ever see a ton of floaters appear out of no where, possibly with some light flashes, you should get to an eye doctor immediately.  There is a chance (1 in 7) that your retina is about to detach from the back of your eye.  If that happens, you have very little time to get it fixed before it effectively dies and you go blind from that eye.
• Floaters can damage the retina by tugging on it, sometimes producing a tear.  When a tear happens, vitreous can invade the opening in the tear, which will ultimately widen the gap and in 50% of these cases will result in the retina eventually becoming fully detached if not repaired via surgery.
• “Light flashes” not caused by actual light, also known as photopsia, will often occur when the photoreceptors in the retina receive stimulation from being touched or from being torn.  This produces an electrical impulse to your brain, which your brain more or less interprets as a light flash.  This physical stimulation is often caused when traction is being applied while the vitreous detachment is taking place.  The flashes should subside when the vitreous finally detaches.
• These flashes will also often temporarily occur when you get a sharp blow to the head.  The sudden jarring causes pressure on the retina; this in turn creates an electrical impulse to the brain which the brain interprets as a flash.

Thanks to About, Earth Clinic, eHow, WiseGeek, All About Vision, WikiDoc, LoveEyeFloaters, and TheBrain!