Floaters and Flashes

These floaters and flashes could be symptoms of a torn or detach

Floaters look like small specks, dots, circles, lines or cobwebs in your field of vision. While they seem to be in front of your eye, they are floating inside. Floaters are tiny clumps of gel or cells inside the vitreous that fills your eye. What you see are the shadows these clumps cast on your retina. This is when the retina pulls away from the back of your eye. This is a serious condition that needs to be treated.

You usually notice floaters when looking at something plain, like a blank wall or a blue sky. What you see isn’t actually the floater itself, but the shadow it casts onto the retina. Floaters move as your eyes move. They appear to zoom away when you try to look directly at them, and drift slowly when your eyes stop moving.

As we age, our vitreous starts to thicken or shrink. Sometimes clumps or strands form in the vitreous. If the vitreous pulls away from the back of the eye, it is called posterior vitreous detachment. Floaters usually happen with posterior vitreous detachment. They are not serious, and they tend to fade or go away over time. Severe floaters can be removed by surgery, but this is seldom necessary.

You are more likely to get floaters if you:

• are near-sighted (you need glasses to see far away)
• have had surgery for cataracts
• have had inflammation (swelling) inside the eye

Flashes

Flashes can look like flashing lights or lightning streaks in your field of vision. Some people compare them to seeing “stars” after being hit on the head. You might see flashes on and off for weeks, or even months. Flashes happen when the vitreous rubs or pulls on your retina.

As people age, it is common to see flashes occasionally.

Flashes and migraines

Sometimes people have light flashes that look like jagged lines or heat waves. These can appear in one or both eyes and may last up to 20 minutes. This type of flash may be caused by a migraine. A migraine is a spasm of blood vessels in the brain.

When you get a headache after these flashes, it is called a “migraine headache.” But sometimes you only see the light flash without having a headache. This is called an “ophthalmic migraine” or “migraine without headache.”

Causes

Floaters can be caused by normal aging of the eye when the vitreous jelly begins to shrink. Other causes of floaters include the sudden release of blood cells from the retinal blood vessels or pigmented cells from underneath the retina into the vitreous jelly. This can occur with the tearing of the retina. It is not always possible to distinguish between the causes of new floaters in the eye, which is why it is essential to have an immediate ophthalmologic examination to look for retinal holes or tears.

Risk Factors

Aging is a large risk factor for new floaters. People who are very nearsighted (high myopes) are at greater risk of developing floaters earlier in life and are also at a greater risk of a retinal tear or detachment.  Inflammation inside the eye (uveitis) and recent intraocular surgery are also risk factors for developing floaters in the eye. 

When floaters and flashes are serious

Most floaters and flashes are not a problem. However, there are times when they can be signs of a serious condition. Here is when you should call an ophthalmologist right away:

• you notice a lot of new floaters
• you have a lot of flashes
• a shadow appears in your peripheral (side) vision
• a grey curtain covers part of your vision

If you experience any of these warning signs, call your doctor right away. You will need to see an ophthalmologist for an eye exam as soon as possible.

Tests and Diagnosis

Most causes of new floaters and flashes can be determined through a clinical exam by an ophthalmologist. If the cause of the symptoms is not seen during a clinical exam, your ophthalmologist may order additional testing, such as an ultrasound of the eye.

If a tear is detected early, treatment can prevent the retina from detaching. Tears can be treated several ways. Pinpoints of laser light can be used to fuse the retina to the back wall of the eye (see “Laser photocoagulation”). Extreme cold, a procedure called cryopexy, does much the same thing.

Cold and laser light can also be paired with the injection of a gas bubble into the eye (pneumatic retinopexy) to repair a detached retina. Two operations, scleral buckling and vitrectomy, can also be used to reattach a retina.

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 clinicians perform and promote laser treatment for benign floaters, but this approach hasn’t been carefully studied in a clinical trial. Floaters can be removed, but for most people the risk to vision from the surgery is greater than the problem posed by the floater. If floaters become a nuisance: move your eyes up and down, or left and right. That can shift the floater and provide temporary relief.