What are floaters?
Floaters are little "cobwebs" or specks that float around in the field of vision. They are small, dark, shadowy shapes that can look like spots, thread-like strands, or squiggly lines. They move as your eyes move and seem to dart away when you try to look at them directly. They do not follow your eye movements precisely, and usually drift when you hold your eyes still.
Most people have floaters and learn to ignore them. A person with floaters usually doesn't notice them until the floaters are large or numerous. Floaters can be more obvious when looking at something with a bright background, such as white paper or a blue sky.
What causes floaters?
Floaters happen when a part of the eye called the vitreous slowly shrinks. The vitreous is a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape. As the vitreous shrinks, it becomes stringy, and the strands that form can cast tiny shadows on the retina, the light-sensitive area at the back of the eye. These shadows can appear as floaters.
In most cases, floaters are a normal part of aging, and do not cause serious problems. They can be annoying at first, but eventually the brain adapts and "learns to ignore" these spots. If you have floaters, you might notice that when you are in areas with new lighting conditions, old floaters that you have long forgotten can "reappear".
However, there are other, more serious causes of floaters. These include infection, inflammation (uveitis), hemorrhaging, retinal tears, and injury to the eye.
Who is at risk of floaters?
Floaters are more likely to develop as a person ages. They are more common in people who are very nearsighted, have diabetes, or who have had cataract surgery.
How are floaters treated?
If floaters don't cause bothersome symptoms, no treatment is needed.
In some people, floaters can be so dense and numerous that they significantly obscure vision. In these rare cases, a vitrectomy surgery might be warranted.
A vitrectomy is a surgery that removes floaters along with the vitreous gel. During surgery, the vitreous is removed and replaced with a salt solution. In less than two days, the body replaces the salt solution with natural fluids, called the aqueous humor. Because the original vitreous is mostly water, the person will not notice any change between the aqueous fluid and the original vitreous.
This surgery can cause complications that might harm vision. These include retinal detachment, retinal tears, and cataract. Most eye doctors will not recommend this surgery unless the floaters cause serious problems with vision.
How are floaters related to retinal detachment?
In some cases, floaters might be a sign of a retinal detachment.
The vitreous lies on top of the retina. When the vitreous detaches from the retina, it is much like an address label being peeled off of an envelope. Sometimes, the label comes off cleanly, but other times, it tears some of the underlying envelope in the process. If the vitreous tears the retina when it detaches, the tear can worsen into a retinal detachment.
Often in a vitreous detachment, a section of the vitreous pulls fine strands away from the retina cleanly and all at once. This causes many new floaters to appear all of a sudden. In most cases, this does not threaten vision or need treatment.
In a retinal detachment, part of the retina is torn and pulled away from its normal position at the back wall of the eye. This can cause a sudden increase in floaters that might come with light flashes or peripheral (side) vision loss.
A retinal detachment is a medical emergency. If left untreated, it can lead to permanent vision loss within two or three days or even blindness in the eye. If you have signs of a retinal detachment, seek treatment immediately.
When is retinal detachment most likely to happen?
Retinal detachment is most likely to happen directly after a vitreous detachment. Normally, it takes three months after a person's first floater for the vitreous to completely detach from the retina. If you have a floater for the first time, you should see your eye doctor regularly during the months following so that he or she can make sure you do not develop a retinal detachment.
If a retinal detachment is caught early, it can usually be treated with laser treatment in the eye doctor's office. If the retinal detachment goes untreated for too long (sometimes for only a few days), a much more serious surgery such as vitrectomy or scleral buckle might be required.
If you have recently had a vitreous detachment, watch carefully for symptoms of retinal detachment, such as flashes of light, a shower of dots, and a pitch-black curtain entering and moving across your vision in any direction. If you have any of these symptoms, especially if you have more than one symptom at the same time, see your eye doctor or go the nearest emergency room immediately.