Floaters--annoying but often benign visual disturbances--occur commonly as people age. Floaters appear as small strings or dots that move quickly when a person tries to focus on them, and are easiest to see when looking at a white wall or other plain surface. The brain learns to ignore floaters over time and no longer "sees" them. Floaters may also sink out of view over time. Floaters that suddenly increase or occur in conjunction with flashes of light can indicate a serious vision problem, and need immediate medical investigation.
Posterior Vitreous Detachment
Posterior vitreous detachment, also known as PVD, occurs in about 60 percent of people older than 70, the University of Illinois Eye and Ear Infirmary reports in The Eye Digest. PVD occurs when the vitreous--the gel that forms the center portion of the eyeball--liquefies in the center and shrinks, which pulls it away from the retina at the back of the eye. Small pieces of collagen that accumulate in the liquefied center of the vitreous appear as floaters, which can appear as strings or clumps of material.
PVD occurs more often in people who are nearsighted or those who have had eye surgery. No treatments exist for PVD. Floaters may sink to the bottom of the vitreous over time and no longer appear visible.
Retinal Tear or Detachment
PVDs can lead to retinal tear or detachment, a serious condition that can result in permanent vision loss if not promptly treated. As the vitreous shrinks, it may pull on the retina (the lining of the back of the eye that perceives light signals and is responsible for vision). The retina may tear, allowing vitreous gel to accumulate beneath the retina. The fluid can completely detach the retina, disturbing vision in the area of detachment. Detachment in the area of the macula, the central point of vision on the retina, can cause severe vision loss.
People with PVD who see flashes of light known as photopsia have a 15 percent chance of developing a retinal tear, All About Vision warns. A sudden increase in floaters accompanied by flashes of light indicates retinal tear in about 14 percent of people, and 50 percent of those with a retinal tear develop a detachment, All About Vision further explains. Retinal tears or detachment both require immediate repair. Treatment includes laser; a freezing technique called cryopexy; pneumatic retinopexy, placement of a gas bubble in the eye to hold the retina in place; and surgical removal of the vitreous and placement of a gas bubble to keep the retina in place.
Tear Film Debris
Debris such as makeup or mucus in the tear film that covers the front of the eye can also cause floaters, the Eye Digest says. Floaters in the tear film often move rapidly or disappear when a person blinks rapidly, unlike floaters caused by PVD.
