Have you ever spotted a small speck floating in the air, only to have it disappear when you tried to look at it directly? Have you noticed streaks of light that you knew weren't really there? If so, you are one of many people who have experienced the common vision phenomenon known as eye floaters and flashes.

The majority of people will experience eye floaters and flashes at some point in their lives. They are a part of the aging process and are generally not of concern. However, in some cases floaters and flashes may be a sign of a more serious condition, which requires medical attention.

Eye Floaters

Eye floaters are small moving spots that appear in your field of vision. They may be especially noticeable when you look at something bright. They can be irritating, but they generally don't interfere with sight.

Eye floaters can appear in many different shapes, such as black or gray dots, squiggly lines, threadlike strands, cobwebs or circles. Occasionally a particularly large eye floater may cast a subtle shadow over your vision, but this tends to occur only in certain types of light

Causes of Eye Floaters

Our eyes are filled with a clear substance known as vitreous gel that helps the eyeball keep its shape while allowing light to pass through to the retina at the back of the eye. Eye floaters occur when the vitreous gel thickens or shrinks as we get older, causing particles or clumps to form. These particles float freely in the gel, blocking the light passing through your eye, and casting shadows on the retina. The shadows are seen as floaters. These may remain in the vitreous gel permanently, and people learn to ignore them.

Sometimes the blood vessels in the retina burst as the shrinking vitreous gel pulls on them. Eye floaters caused by this kind of minor haemorrhaging create little black dots in your field of vision. Although these usually resolve themselves as the blood is reabsorbed by the body, they should be investigated.

Rarely, eye floaters can result from eye surgery, disease or injury, diabetic conditions, or even more rarely, eye tumours.

Eye Flashes

Eye flashes should always be taken more seriously. Any physical stimulation to the retina causes an electrical impulse which is interpreted as a flash of light by the brain. As an example, the shrinking vitreous may pull or rub on the retina causing a flash or flicker of light. If left untreated this could result in a retinal tear or detachment.

Flashes and floaters can be associated with the aura of an oncoming migraine headache. In these instances, the eye flashes often look like jagged lines or heat shimmers that last between 10 and 20 minutes.

Time Is Your Best Treatment

Eye floaters normally require no treatment. Over time, as the brain learns to filter out the visual interference, most people notice floaters less and less, or learn to live with them.

Occasionally, the vitreous gel is surgically removed from the eye and replaced with a saline solution, but it is rare for floaters to become problematic enough to consider this treatment.

When to Seek Medical Attention

If you only have a few eye floaters that don’t change over time, it usually does not indicate a serious problem, but sometimes eye floaters are a sign of a more serious condition, and medical intervention is essential.

See an eye care practitioner immediately if you notice an increase in the number of eye floaters, especially if the changes occur suddenly, or if there is eye pain with the floaters.

Immediate medical attention is especially important if the floaters are accompanied by flashes of light or a loss of peripheral vision. These symptoms may be caused by retinal detachment, retinal tear or bleeding within the eye.

Halos and Glare

Halos are bright circles of light that appear to surround the source of light, such as a lamp or oncoming headlights of a car. Glare is light that enters the eye and, rather than helping vision, interferes with it. While halos typically occur in dim light, glare is more common during the bright light of day.

Causes of Halos and Glare

Halos and glare are usually a normal response to bright lights, but they may sometimes be associated with an eye problem. They are a common symptom of cataracts, as the cloudiness of the lens affects the way light is perceived.

Eye problems that prevent the eye from effectively focusing light on the retina may cause halos and glare. These include shortsightedness, farsightedness, astigmatism, presbyopia (vision problems due to aging), and certain eye surgeries.

Treating and Preventing Halos and Glare

If halos or glare bother you, discuss this with your optometrist who may prescribe specific lenses for your visual conditions, which may help reduce the effects of glare and halos.

Wear sunglasses to reduce glare during the day. Polarised sunglasses may be particularly helpful.

Use your vehicle's visor while driving to keep direct sunlight out of your eyes.