What does it mean when you see spots before your eyes?

It is most probably not your imagination; you are probably experiencing it. Vitreous floaters are usually perceived as spots. The vitreous is the clear liquid that fills the eye. It is jelly-like, almost like clear gelatin.

The Normal Eye

The human eye is like a hollow globe filled with fluid. Behind the lens, and filling all the posterior portion of the eye, is the Vitreous Humor. It is “normally” a transparent viscous liquid, similar to egg white in consistency. A thin membrane that is attached to the retina contains the vitreous humor. Before the picture is focused sharply on the retina, the light passes through the clear vitreous fluid of the eye, just as the light would pass through the “air” in a camera. The vitreous must always be crystal clear if the eye is to provide crystal clear vision. Any spots in the vitreous will appear as black spots to the viewer.

Should I Worry About Vitreous Floaters?

Generally, vitreous floaters are of little importance and are part of the aging process. Romans used to call these floaters “muscae volitantes”, or flying flies. Many patients perceive these as annoyances that come and go. Floaters can go away when gravity pulls them down below the line of sight. They may come back if something shakes the fluids of the eye, raising them back into the field of vision. Almost everyone will see floaters at one time or another. Floaters sometimes interfere with vision and they can be quite annoying. If a floater appears directly in front of your line of vision, the best thing you can do is to move the eye. This causes the internal liquids to move making the floater move out of your line of sight.

As we age, the vitreous gel may liquefy. Eventually this thinned out gel can collapse pulling the membrane that surrounds it away from the retina. This can be called either a vitreous separation or vitreous detachment. These terms are used interchangeably and should not be confused with a retinal detachment, which is much more serious. Frequently, the collapsed vitreous gel will have many compressed strands and cells in it. The patient may see this as floaters, a web or a veil in front of his eyes. This may persist until it disintegrates or drops below the line of sight. These are especially common in myopic (nearsighted) people, after eye trauma or after surgery. This, in itself is not dangerous. Other less common causes of floaters are inflammation inside the eye or whitish deposits formed in the vitreous humor (known as Asteroid Hyalosis). Patients usually learn to tolerate these spots.

Floaters can have varying degrees of significance, depending on what causes them, most floaters are harmless. However, there are more significant causes for floaters. Sometimes, the vitreous membrane pulls and creates a tear in the retina. Unless this tear is closed, fluid can get through this hole in the retina and cause a retinal detachment. Often the patient sees a shower of floaters. There may be thousands of these floaters, representing blood cells liberated from a break in a retinal blood vessel caused by the retinal tear. There may be so many floaters that it appears as though a bag of pepper has broken or that a blizzard of black snow has occurred. Severe flashes of light may occur.

What Causes the Flashes?

When the vitreous fluid inside the eye moves, the vitreous membrane may pull on the retina, causing a flashing sensation, although in fact there is not such light inside the eye. A similar sensation sometimes happens when you hit your eye and see “stars.” Flashes can appear once or from time to time over several weeks. The flashes can be associated with a great number of new floaters and even with partial loss of the visual field. These symptoms may be associated with a retinal detachment. Sometimes there are no floaters, only flashes. Sometimes a retinal tear gives no warning at all. It is not always possible for the patient to assess the significance.

What Can I Do About Vitreous Floaters or Flashes?

Without an exam done by your eye care specialist, you cannot know if your floaters or flashes are serious or if they represent any danger to your eye. A significant change in your floaters should alert you to the fact that there has been a change inside your eye. It is wise to have these changes evaluated quickly to safeguard your eyesight. An early diagnosis of a retinal tear can result in a five minute, painless laser treatment with excellent probability of success. Delay in diagnosis can result in the need for major eye surgery in the operating room with lesser probabilities for success. This eye exam usually includes a detailed observation of the retina and vitreous humor. Drops that dilate the pupil are necessary in the examination the peripheral retina.

Other Type of Flashes

Flashes that look like a jagged line or “heat waves” and last from 10 to 20 minutes, in both eyes, are often due to migraine headaches caused by a spasm of the cerebral blood vessels. If they are followed by a headache, they are called cephalic migraines. However, these jagged lines or “heat waves” can happen without the headache and they are called ophthalmic migraines.