Flashes and Floaters: When Should You Be Concerned?

What Are Flashes and Floaters?

Eye floaters are small spots, lines, strings, or shapes that appear to move across your field of vision. Patients often describe them as looking like gnats, black pepper, cobwebs, dots, or blobs. They may be especially noticeable when looking at a bright background, such as a white wall or clear sky.

Floaters are often caused by changes in the vitreous, the clear gel-like substance that fills the inside of the eye. As we age, the vitreous naturally changes and can form small clumps or strands that cast shadows on the retina, creating the appearance of floaters.

Flashes of light in the vision, also called photopsias, are often described as looking like a camera flash, lightning streak, or flickering light in the peripheral vision. Flashes can occur when the vitreous pulls or tugs on the retina.

Flashes and floaters may occur together or separately.

When Are Flashes and Floaters Normal?

Having a few longstanding floaters that do not suddenly change is common, particularly as you get older. Some people become so accustomed to their floaters that they barely notice them unless they are looking at a bright background.

An occasional brief flash may also occur and does not always indicate a serious retinal problem.

However, new or suddenly worsening flashes and floaters should not be ignored. Because it can be difficult to determine the cause based on symptoms alone, a dilated retinal examination may be necessary to make sure there is not a retinal tear or other problem.

When Should You Worry About Flashes and Floaters?

Certain changes in your vision can be warning signs of a retinal tear or retinal detachment and require prompt evaluation.

Contact a retinal specialist right away if you experience:

• A sudden burst or significant increase in new floaters
• A new floater that looks like a cobweb or spiderweb
• Frequent or persistent flashes of light
• A shadow, curtain, or veil appearing in your vision
• New areas of missing or decreased vision
• New flashes or floaters accompanied by a noticeable change in vision

A curtain or shadow over your vision is particularly concerning because it can be a symptom of retinal detachment, which is a medical emergency.

If you experience these symptoms, you should be evaluated by an eye care professional promptly.

Why Can New Flashes and Floaters Be a Sign of a Retinal Problem?

As the vitreous inside the eye naturally changes with age, it can begin to separate from the retina. This is known as a posterior vitreous detachment (PVD).

A PVD is common and does not always cause a serious problem. However, as the vitreous separates, it can sometimes pull hard enough on the retina to create a retinal tear. Fluid may then travel through the tear and underneath the retina, potentially causing a retinal detachment.

This is why a sudden onset of flashes and floaters should be evaluated even if your central vision still seems normal.

What Happens During a Retinal Examination for Flashes and Floaters?

If you are evaluated for new flashes or floaters, your retinal examination may include checking your vision and eye pressure, dilating your pupils, retinal imaging, and a thorough examination by the retina specialist.

OCT Imaging

Optical coherence tomography (OCT) is a noninvasive imaging test that produces detailed cross-sectional images of the retina. You can think of it like looking at the individual layers of a cake after it has been sliced. OCT allows your retina specialist to examine the different layers of the retina in detail.

Fundus Photography

Fundus photographs are detailed color images of the retina. These photographs allow your doctor to document the appearance of the retina and can help diagnose and monitor retinal conditions.

Dilated Retinal Examination

Dilation is an important part of a thorough retinal examination. Dilating drops temporarily enlarge the pupil, allowing your retina specialist to see more of the inside of your eye.

Without dilation, the pupil naturally constricts in response to the bright light used during an eye examination, which can limit the doctor's view of the retina. A dilated examination provides a much wider view and helps the doctor look carefully for retinal tears, detachments, or other abnormalities.

Don't Ignore Sudden Changes in Your Vision

Most people will notice a floater at some point in their lives, and many floaters are harmless. However, sudden new floaters, persistent flashing lights, or a curtain or shadow in your vision should always be taken seriously.

Early detection of a retinal tear can sometimes allow it to be treated before it progresses to a retinal detachment.

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Main Line Retina is a boutique retina practice providing personalized care lead by Dr. Hilary Brader, who trained at strong academic institutions (Penn, Harvard) and has been recognized for multiple years as "Top Doctor" by Philadelphia Magazine and Castle Connolly.  Main Line Retina has been recongized for its Commitment to Quality by the American Society of Retina Specialists and serves patients across the Main Line as well as Philadelphia and Delaware County, and is a close drive from  Haverford, Bryn Mawr, Wayne, Bala Cynwyd, Media, Havertown and surrounding communities.