What are floating bodies?
Floating bodies appear as gray or black dots, lines, or "spider threads" in front of the eyes. As the eyes move, the floating bodies move as well. They do not follow your eye movements precisely because they usually drift when the eyes begin to move or stop moving.
Floating bodies are caused by clumps or small pieces of material suspended in the glassy jelly (called vitreous humor) that fills the back of the eye. Floating bodies cast shadows on the light-sensitive retina. It's really the shadow of the floating body that you see. Floating bodies can have a variety of causes, some serious and some less serious (see below).
What are flashes?
Flashes are sensations of light, when no light is really there. They can appear as tiny bright lights or as portions of lightning in the sky.
Flashes can occur when the vitreous humor pulls on the retina or tears it. These flashes usually only last for a second or so, but usually reappear several times. They become more obvious with the movement of the eyes or in a dark room.
Some individuals with headaches or migraines may experience a different type of flash. These will usually have a pulsating motion where the light exhibits constant deformations for a period of about fifteen minutes. They usually appear in the center of the visual field and progress slowly toward the edges of the field of view. A throbbing headache located on one side of the head may occur after the disappearance of the flashes.
Floating bodies and flashes: are they serious?
Floating bodies are common. The ones you've had for years and have little change are generally benign. It is the sudden start of one or large floating bodies that can be alarming. The beginning of the flashes can also be serious.
A person having flashes or a sudden start of one or many important floating bodies should be promptly examined by an optometrist. The optometrist will perform a fundus examination with dilation of the pupils (examination of the vitreous and retina with special equipment after administering drops to enlarge the pupils).
WHAT DOES THE OPTOMETRIST LOOK FOR IF I HAVE FLASHS AND / OR FLOATING BODIES?
Your optometrist will look inside the eye to see if there is any disease or damage to the vitreous or retina. The sudden onset of floating bodies or flashes is often due to a separation of the vitreous retina. When this happens, the retina can tear or peel off in about 10% of cases. In most cases, the retina is not torn, and your optometrist will examine your eye again at a later date.
WHAT TO DO ABOUT FLOATING BODIES AND FLASHES?
Your flashes may disappear after a few days or weeks. This can be true even if you have a tear or retinal detachment! It is therefore important to be examined by an optometrist even if your flashes disappear on their own.
Floating bodies tend to stay longer than flashes. In most cases, they decrease gradually after weeks or months. Often they do not disappear completely. Most people learn to ignore them. Floating bodies, such as flashes, may disappear even if a tear or detachment of the retina is present. Again, you should be examined even if the floating bodies seem to be leaving.
If you have a retinal tear or detachment, your optometrist will talk to you about the treatment (see the retinal detachment section).