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.
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.
Eye 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.
What Causes Eye Flashes?
Ordinarily, light entering your eye stimulates the retina. This produces an electrical impulse, which the optic nerve transmits to the brain. The brain then interprets this impulse as light or some type of image.
If the retina is mechanically stimulated (physically touched), a similar electrical impulse is sent to the brain. This impulse is then interpreted as a “flicker” of light.
When the retina is tugged, torn or detached from the back of the eye, a flash or flicker of light commonly is noticed. Depending on the extent of the tear or detachment, these flashes of light might be short-lived or continue indefinitely until the retina is repaired.