Health Topics

Your Vision: Understanding ‘Flashes’ and ‘Floaters’

Seeing the Light

Ever see something drifting across the sky – then discover it’s actually drifting across your eye?

That would be a "floater." Floaters are bits of debris in the interior of your eye that appear when you look at something white or very bright. “People describe them as cobwebs, spiderwebs, bubbles or even ‘tadpoles’,” says Arun Singh, MD, of Cleveland Clinic Cole Eye Institute.

Dr. Singh, an ophthalmologist, or physician specializing in eye disorders, sees patients with floaters and “flashes” every day. Flashes often accompany floaters, and look like a camera flash going off when you close your eyes or wake up in the middle of the night.

Flashes and floaters can be caused by:

  • detachment of the jelly-like “vitreous” from the retina, the innermost light-sensitive layer of the eye. The most common cause of floaters and flashes, posterior vitreous detachment occurs naturally as we get older, typically around ages 55 to 60. When it occurs in one eye, it usually follows in the other.
  • retinal tear or detachment, most frequently due to vitreous detachment, near-sightedness (myopia), or any kind of trauma or surgery, such as cataract surgery
  • hemorrhage, or leakage of blood, from a tiny vessel in the retina. The second most common cause of flashes and floaters, hemorrhages can occur when a stronger pull on the retina tears a blood vessel or when abnormal blood vessels develop in the eye in conditions such as diabetes. Small hemorrhages may disappear on their own, but larger hemorrhages that persist may require surgery.
  • infection, such as herpetic retinal infection, and inflammation, such as uveitis (involving the middle lining of the eye).
  • tumors of the eye – while rare, these must be ruled out, says Dr. Singh, an expert on ocular tumors.

Flashes are more ominous than floaters, notes Dr. Singh, signaling an irritation of the retina from tugging, tearing, inflammation or infection. “When the retina is stimulated, the brain sees it as light because it only has photoreceptors,” he explains.

A mild tug can progress to a retinal tear, which can progress to retinal detachment – a medical emergency. Torn or detached retinas must be promptly repaired by laser surgery or another procedure to preserve vision.

When to see an ophthalmologist

“If you’ve had floaters for 40 years, you don’t have to go to your ophthalmologist,” advises Dr. Singh. “But if you have ‘recent-onset’ floaters – if they weren’t there yesterday or last week – see an ophthalmologist that day or the next.”

Prompt appointments are especially important if you see many floaters or if floaters are accompanied by flashes.

Despite the fast action required, there is no need to panic, says Dr. Singh. Flashes and floaters are just symptoms of a problem that most often turns out to be minor.

3 tips to keep your eyes – and vision – healthy over the years:

  1. Eat a balanced and healthy diet.
  2. Quit smoking – it’s a huge risk factor for macular degeneration. Loss of sight in the macula, in the center of the retina, is a common cause of blindness in the elderly.
  3. Wear sunglasses when in bright light for extended periods of time to protect against ultraviolet light exposure.