Flashes and floaters
What are flashes and floaters?
Floaters are little “cobwebs” or specks that float about in your 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 your eyes stop moving.
Most people have floaters and learn to ignore them; they are usually not noticed until they become numerous or more prominent. Floaters can become apparent when looking at something bright, such as white paper or a blue sky.
Flashes are brief arcs of light seen typically in a dark environment. This occurs when the vitreous gel pulls on the surface of the retina during the process of vitreous detachment (see below). These symptoms are exacerbated with rapid head or eye movements. Do not try to reproduce these symptoms by looking rapidly side to side or by turning your head rapidly.
What causes floaters?
Floaters occur when the vitreous, a gel-like substance that fills about 80 percent of the eye, slowly shrinks.
As the vitreous shrinks, it becomes somewhat stringy, and the strands can cast tiny shadows on the retina. These are floaters.
In most cases, floaters are part of the natural aging process and simply an annoyance. They can be distracting at first, but eventually tend to “settle” at the bottom of the eye, becoming less bothersome. They usually settle below the line of sight and do not go away completely.
However, there are other, more serious causes of floaters, including infection, inflammation (uveitis), hemorrhaging, retinal tears, and injury to the eye.
Who is at risk for floaters?
Floaters are more likely to develop as we age and are more common in people who are very nearsighted, have diabetes, or who have had a cataract operation.
How are floaters treated?
For people who have floaters that are simply annoying, no treatment is recommended.
On rare occasions, floaters can be so dense and numerous that they significantly affect vision. In these cases, a vitrectomy, a surgical procedure that removes floaters from the vitreous, may be needed.
A vitrectomy removes the vitreous gel, along with its floating debris, from the eye. The vitreous is replaced with a salt solution. Because the vitreous is mostly water, you will not notice any change between the salt solution and the original vitreous.
This operation carries significant risks to sight because of possible complications, which include retinal detachment, retinal tears, and cataract. Most eye surgeons are reluctant to recommend this surgery unless the floaters seriously interfere with vision.
Floaters and retinal tear or detachment
Sometimes a section of the vitreous pulls the fine fibers away from the retina all at once, rather than gradually, causing many new floaters to appear suddenly. This is called a vitreous detachment, which in most cases is not sight-threatening and requires no treatment.
However, a sudden increase in floaters, possibly accompanied by light flashes or peripheral (side) vision loss, could indicate a retinal tear or detachment. A retinal detachment occurs when any part of the retina, the eye’s light-sensitive tissue, is lifted or pulled from its normal position at the back wall of the eye.
A retinal detachment is a serious condition and should always be considered an emergency. If left untreated, it can lead to permanent visual impairment within two or three days or even blindness in the eye.
Those who experience a sudden increase in floaters, flashes of light in peripheral vision, or a loss of peripheral vision should have an eye care professional examine their eyes as soon as possible.
What is a vitreous detachment?
Most of the eye’s interior is filled with vitreous, which is a gel like substance. There are millions of fine fibers intertwined within the vitreous that are attached to the surface of the retina, the eye’s light-sensitive tissue. As we age, the vitreous slowly shrinks, and these fine fibers pull on the retinal surface. Usually the fibers break, allowing the vitreous to separate and shrink from the retina. This is a vitreous detachment.
In most cases, a vitreous detachment, also known as a posterior vitreous detachment, is not sight-threatening and requires no treatment.
Who is at risk for a vitreous detachment?
A vitreous detachment is a common condition that usually affects people over age 50, and is very common after age 80. People who are nearsighted are also at increased risk. Those who have a vitreous detachment in one eye are likely to have one in the other, although it may not happen until years later.
What are the symptoms of a vitreous detachment?
As the vitreous shrinks, it becomes somewhat stringy, and the strands can cast tiny shadows on the retina that you may notice as floaters, which appear as little “cobwebs” or specks that seem to float about in your field of vision. If you try to look at these shadows they appear to quickly dart out of the way.
One symptom of a vitreous detachment is a small but sudden increase in the number of new floaters. This increase in floaters may be accompanied by flashes of light (lightning streaks) in your peripheral, or side, vision. In most cases, either you will not notice a vitreous detachment, or you will find it merely annoying because of the increase in floaters.
How does vitreous detachment affect vision?
Although a vitreous detachment does not threaten sight, once in a while some of the vitreous fibers pull so hard on the retina that they create a retinal tear which can lead to a retinal detachment. Both of these conditions are sight-threatening and should be treated immediately.
If left untreated, a detached retina can lead to permanent vision loss in the affected eye. Those who experience a sudden increase in floaters or an increase in flashes of light in peripheral vision should have an eye care professional examine their eyes as soon as possible.
The only way to diagnose the cause of the problem is by a comprehensive dilated eye examination. If the vitreous detachment has led to a retinal tear or detached retina, early treatment can help prevent loss of vision.