I have been experiences them for years! You I am a frequent evening walker in the lawns opposite to the Vice Regal lodge in the DU north campus. I often also indulge in some yoga there. Often when i lie down in the lawns on my back, i see tiny diffuse spots floating in my field of view, particularly when i am looking at nothing else but the blue sky.
Something like in the following image
I have often wondered about their genesis, but could not come forward with an explanation. Then I found the question in the book " The flying Circus of Physics" and after reading the answer there i decided to explore a bit more! I was not very disappointed by my google search! Here I quote from an informative article that I found:
| Marilyn Haddrill wrote: |
Eye floaters are those tiny spots, specks, flecks and "cobwebs" that drift aimlessly around in your field of vision. While annoying, ordinary eye floaters and spots are very common and usually aren't cause for alarm.
Floaters and spots typically appear when tiny pieces of the eye's gel-like vitreous break loose within the inner back portion of the eye.
When we are born and throughout our youth, the vitreous has a gel-like consistency. But as we age, the vitreous begins to dissolve and liquefy to create a watery center.
Some undissolved gel particles occasionally will float around in the more liquid center of the vitreous. These particles can take on many shapes and sizes to become what we refer to as "floaters."
You'll notice that these types of spots and floaters are particularly pronounced when you peer at a bright, clear sky or a white computer screen. But you can't actually see tiny bits of debris floating loose within your eye. Instead, shadows from these floaters are cast on the retina as light passes through the eye, and those shadows are what you see.
You'll also notice that these specks never seem to stay still when you try to focus on them. Floaters and spots move when your eye moves, creating the impression that they are "drifting."...........
What Causes Eye Floaters and Spots?
As mentioned above, posterior vitreous detachments or PVDs are common causes of vitreous floaters. Far less commonly, these symptoms can be associated with retinal tears or detachments that may be linked to PVDs.
Clumps occur when the vitreous gel begins to liquefy or shrink, usually with aging, and detaches from the retina.
But what leads to vitreous detachments in the first place?
As the vitreous gel fills the inside of the back of the eye, it presses against and actually attaches to the retina. Over time, the vitreous becomes more liquefied in the center. This sometimes means that the central, more watery vitreous cannot support the weight of the heavier, more peripheral vitreous gel.
Vitreous gel then collapses into the central, liquefied vitreous. While this occurs, the peripheral vitreous detaches from the inner back of the eye where the retina is located.
Floaters resulting from a vitreous detachment are then concentrated in the more liquid vitreous found in the interior center of the eye.
More than half of all people by the time they are 80 will have had a vitreous detachment.* If you are among the 40 percent of people with PVDs who also experience light flashes, then you have about a 15 percent chance of also developing a retinal tear.**
Light flashes during this process mean that traction is being applied to your retina while the PVD takes place. Once the vitreous finally detaches and pressure on the retina is eased, the light flashes should gradually subside.
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