Many people experience floaters and/or flashes over the course of their lives. Floaters have the appearance of small shapes, lines, specks, or cobwebs moving around in front of your eye. If you’ve ever seen what appears to be a bright burst of light or streaks of light in front of your eye, you may have experienced flashes. Flashes and floaters are very common and are often harmless. They sometimes require no treatment, disappearing on their own over time. At times, however, floaters or flashes, especially those that appear suddenly, or increase in number, can be signs of a serious eye problem requiring immediate medical attention.
Floaters are caused by small gel or cell clumps that form inside the vitreous—the clear gel-like substance in the middle of your eye— as it shrinks over time and contracts away from the retina, at the back of the eye. The clumps cast shadows on the retina, the part of the eye that processes light rays, causing it to appear as though dark shapes or specks are floating in front of the eye.
While the shrinking and detachment of the vitreous from the retina can happen to anyone as they age, the condition is more common in people who have undergone YAG laser eye surgery or cataract surgery, have experienced inflammation in the eye, or are nearsighted. While a shrinking vitreous itself will not harm the eye, it may pull on the retina and cause a tear. A tear can, in turn, lead to bleeding inside the eye that may cause you to see new floaters, and can also result in a retinal detachment. Because a detached retina can lead to permanent loss of vision if not promptly treated, you should contact your eye doctor immediately if you experience any new floaters or an increase in the number of floaters.
Sometimes, flashes of light are a sign of a condition known as a migraine, a spasm of blood vessels in the brain. In these cases, the flashes often take the form of jagged lines or waves and appear in both eyes for several minutes. You’ve probably heard of migraine headaches, but migraines can also occur without causing head pain. These are referred to as ophthalmic migraines.
Remember that the sudden appearance of a significant number of floaters, especially if they are accompanied by flashes of light or other vision disturbances, could indicate a detached retina or other serious problem in the eye. A retinal detachment or tear is an emergency, requiring immediate medical attention.
If you suddenly see new floaters or flashes of light, contact your eye doctor without delay.