SPOTS BEFORE YOUR EYES
Many people experience eye flashes and floaters at some point in their lives. Many people confuse them, thinking they have floaters when they have flashes and vice versa. Although they both originate from within the eye itself, they differ in terms of appearance and causes. Eye floaters are freely floating clusters that gently drift in the visual field. They come in various shapes and sizes - to some people, the floater appears to be a spot, while others see a thread, and still, others see them as clear bubbles. In fact, what is being seen is the shadow being cast onto the retina by a solid mass. Eye flashes are visual sensations of bright light that are not caused by light sources in the environment. They may appear as quick bursts of light or streaks of lightning, usually in peripheral vision.
What causes eye floaters and flashes?
Eye floaters are caused by the formation of clusters of collagen in the vitreous part of the eye. The vitreous humor is the gel-like fluid that fills the large cavity between the lens at the front of the eye and the retina at the back of the eye. As we age, the collagen fibers begin to clump together, forming masses of different shapes and sizes which float freely throughout the vitreous. They move as the eyes move but seem to dart away when you try to look at them directly. These clumps cast shadows on the retina and are perceived to be outside of the eye when they are in fact within the eye itself.
Flashes result as the vitreous shrinks over time and pull on or tears away from the retina. The stimulation of the retina causes it to send a signal to the brain which interprets it as light even though there is no light present. Flashes usually occur in one eye at a time and last only a second or two, but can persist for weeks or even months. These flashes differ from the flashes associated with migraines, which are characterized by shimmering jagged lines which occur in both eyes and can last up to 20 minutes. They are commonly followed by a headache.
What are the risk factors for floaters and flashes?
Because the vitreous shrinks with age, about 25% of people experience floaters by the age of 60. This number rises gradually. Floaters appear more often in people who are shortsighted, those who have had cataract surgery or a previous eye injury, and those with diabetes. Eye flashes following trauma are of concern, particularly if followed by decreased vision.
Are floaters and flashes dangerous?
Typically, eye floaters are part of the normal aging process and are of little medical concern, particularly if they have developed gradually and haven't changed much over time. It is extremely rare for them to interfere with vision. In some people, floaters remain relatively constant for many years, while in others they fade with time. Sudden onset or increase in the number of flashes or floaters or a 'curtain' that comes down in the field of vision could indicate a problem. Similarly, if floaters are accompanied by sudden flashes of light, there may be a retinal detachment and medical attention should be sought as soon as possible to rule out a serious problem and avoid permanent vision loss.
Symptoms of retinal detachment include bright flashes of light, especially in peripheral vision, blurred vision, floaters, shadows, or blindness in a part of the visual field of one eye, and sudden rapid decline in sharp central vision. A retinal detachment is usually painless, so the occurrence of any of these warning signs needs to be taken seriously. If detected early, a retinal detachment can be treated, and further vision problems can be prevented.
Living with floaters
If your floaters aren't a sign of retinal damage, they may disappear, become less noticeable, or stay and become irritating. Some people report improvement after laser surgery to break up floaters and make them less noticeable, while others choose to live with the floaters. If floaters become a nuisance, it is suggested that moving your eyes up and down, or left and right can shift the floater and provide temporary relief. Regular visits to your optometrist for an eye examination will ensure that the floaters and flashes remain stable, are normal, and are not indicative of a problem.