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.
Floaters become more mobile and visible as the vitreous liquifies with age and detaches from the retina.
You'll notice that these types of spots and eye 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."
The sudden appearance of these symptoms could mean that the vitreous is pulling away from your retina or that the retina itself is becoming dislodged from the inner back of the eye that contains blood, nutrients and oxygen vital to healthy function. When the retina is torn, vitreous can invade the opening and push out the retina — leading to a detachment.
In cases of retinal tear or detachment, action must be taken as soon as possible so that an eye surgeon can reattach the retina and restore function before vision is lost permanently.
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.
Eye floaters resulting from a vitreous detachment are then concentrated in the more liquid vitreous found in the interior center of the eye.
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.